#include <bits/stdc++.h>

using namespace std;

#define endl '\n'
#define int long long

const int N = 1e5 + 20;

int m[N];

struct comp {
    bool operator() (const pair <int , int> &lhs, const pair <int , int> &rhs) const {
        return lhs.first > rhs.first;
    }
};


int32_t main()
{
    ios_base :: sync_with_stdio(0);
    cin.tie(0);

    set <pair <int , int> , comp> s;
    s.insert({1 , 1});
    s.insert({1 , 2});
    s.insert({1 , 3});
    s.insert({1 , 4});

    for(auto x : s)
        cout << x.first << " " << x.second << endl;
    return 0;
}

I expected the above code to print : 1 1 1 2 1 3 1 4

But it only prints :

1 1

However that works fine without the comparator. Why is this strange thing happening?