// -------------------- Includes -------------------- //
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <stdio.h>
#include <cstdlib>
#include <stdlib.h>
#include <array>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <math.h>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <list>
#include <iterator>
#include <numeric>
#include <complex>
#include <tuple>
#include <utility>
#include <cassert>
#include <assert.h>
#include <climits>
#include <limits.h>
#include <ctime>
#include <time.h>
#include <random>
#include <chrono>
#include <fstream>
using namespace std;

// -------------------- Typedefs -------------------- //

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;

// -------------------- Defines -------------------- //

#define pr pair
#define mpr make_pair
#define ff first
#define ss second

#define mset multiset
#define mmap multimap
#define uset unordered_set
#define umap unordered_map
#define umset unordered_multiset
#define ummap unordered_multimap
#define pqueue priority_queue

#define sz(x) (int((x).size()))
#define len(x) (int((x).length()))
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()

#define pf push_front
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ft front
#define bk back

#define lb lower_bound
#define ub upper_bound
#define bs binary_search

// -------------------- Constants -------------------- //

const int MAX = int(1e9 + 5);
const ll MAXL = ll(1e18 + 5);
const ll MOD = ll(1e9 + 7);
const ll MOD2 = ll(998244353);

// -------------------- Functions -------------------- //

void fastio()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	return;
}

void precision(int x)
{
	cout.setf(ios::fixed | ios::showpoint);
	cout.precision(x);
	return;
}

ll gcd(ll a, ll b)
{
	if (a > b) {
		swap(a, b);
	}
	if (a == 0) {
		return b;
	}
	if (a == b) {
		return a;
	}
	return gcd(b % a, a);
}

ll lcm(ll a, ll b)
{
	return a / gcd(a, b) * b;
}

bool is_prime(ll a)
{
	int i;
	for (i = 2; i * i <= a; i++) {
		if (a % ll(i) == 0) {
			return false;
		}
	}
	return true;
}

bool is_square(ll a)
{
	ll b = ll(sqrt(a));
	return (b * b == a);
}

bool is_cube(ll a)
{
	ll b = ll(cbrt(a));
	return (b * b * b == a);
}

int digit_sum(ll a)
{
	int sum = 0;
	while (a) {
		sum += int(a % 10);
		a /= 10;
	}
	return sum;
}

ll binpow(ll a, int b)
{
	ll ans = 1;
	while (b) {
		if ((b & 1) == 1) {
			ans *= a;
		}
		b >>= 1;
		a *= a;
	}
	return ans;
}

ll binpow_by_mod(ll a, ll b, ll mod)
{
	ll ans = 1;
	while (b) {
		if ((b & 1) == 1) {
			ans *= a;
			ans %= mod;
		}
		b >>= 1;
		a *= a;
		a %= mod;
	}
	return ans;
}

ll factorial(int a)
{
	int i;
	ll ans = 1;
	for (i = 2; i <= a; i++) {
		ans *= ll(i);
	}
	return ans;
}

ll factorial_by_mod(int a, ll mod)
{
	int i;
	ll ans = 1;
	for (i = 2; i <= a; i++) {
		ans *= ll(i);
		ans %= mod;
	}
	return ans;
}

// -------------------- Solution -------------------- //

/*const int N = 200005;
int a[N];
int n;*/

bool check(mset<int> s, int k)
{
	set<int> st;
	for (auto it = s.begin(); it != s.end(); it++) {
		st.insert(*it);
	}
	return (sz(st) < k);
}

void solve()
{
	int i, j;
	int n, k;
	cin >> n >> k;

	//change n into a vector so that the indexes appear
	vector<int> v;
	while (n) {
		v.pb(n % 10); //pb is push_back
		n /= 10;
	}
	reverse(all(v)); //all(v) is v.begin(), v.end()

	set<int> p;
	for (int l = 0; l < sz(v); l++) { //sz is size
		p.insert(v[l]);
		if (sz(p) > k) { //if p contains more than k distinct digits
			i = l;
			break;
		}
	}

	if (sz(p) <= k) { //if p = n
		//print n
		for (int l = 0; l < sz(v); l++) {
			cout << v[l];
		}
		cout << endl;
		return;
	}

	p.erase(p.find(v[i]));

	auto it = p.ub(v[i]); //ub is upper_bound

	if (it != p.end()) { //if x exists
		int x = *it;
		v[i] = x;
		for (int l = i + 1; l < sz(v); l++) {
			v[l] = *p.begin(); //change the all remaining digits of n into the smallest number in p
		}

		//print answer
		for (int l = 0; l < sz(v); l++) {
			cout << v[l];
		}
		cout << endl;
		return;
	}
	mset<int> s; //mset is multiset

	j = i - 1;

	for (int l = 0; l < j; l++) {
		s.insert(v[l]);
	}

	for (j; j >= 0; j--) {
		int a = v[j];
		if (s.find(a) == s.end()) { //s doesn't contain a
			v[j] = a + 1;
			s.insert(a + 1);
			if (check(s, k)) { //if s contain less than k distinct digits
				for (int l = j + 1; l < sz(v); l++) {
					v[l] = 0;
				}
			}
			else {
				for (int l = j + 1; l < sz(v); l++) {
					v[l] = *s.begin();
				}
			}

			//print answer
			for (int l = 0; l < sz(v); l++) {
				cout << v[l];
			}
			cout << endl;
			return;
		}
		auto it = s.ub(a);
		if (it != s.end()) { //if b exists
			int b = *it;
			v[j] = b;
			s.insert(b);
			if (check(s, k)) { //if s contain less than k distinct digits
				for (int l = j + 1; l < sz(v); l++) {
					v[l] = 0;
				}
			}
			else {
				for (int l = j + 1; l < sz(v); l++) {
					v[l] = *s.begin();
				}
			}
			//print answer
			for (int l = 0; l < sz(v); l++) {
				cout << v[l];
			}
			cout << endl;
			return;
		}
		s.erase(s.find(v[j - 1])); //delete digit before a
	}
	return;
}

void precalc()
{
	return;
}

int main()
{
	fastio();

	precalc();

	int tests = 1, tc;
	cin >> tests;
	for (tc = 1; tc <= tests; tc++) {
		solve();
	}

	//cout << db(clock()) / CLOCKS_PER_SEC << endl;

	return 0;
}

/*
	# # # #   # # # #   # # # #   #       #    #       #     #
	   #      #         #     #    #     #    # #      #   #
	   #      # # # #   #     #     #   #    #   #     # #
	   #            #   #     #      # #    # # # #    #   #
	   #      # # # #   # # # #       #    #       #   #     #
*/