#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define rep(i,a,b) for(int i = a; i <= b; i++)
#define mod 1000000007
#define mx 100003
#define ss second
#define ff first
#define ld long double
#define pii pair<int, int>
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;

unsigned long long int dp[mx];
int arr[mx]={0};

int main()  {
memset(dp,-1,sizeof(dp));

int n,temp;
cin >> n;

for(int i=0; i<n; i++)  {
    cin >> temp;
    arr[temp]++;
}

dp[1]=arr[1];
dp[0]=0;
for(int i=2; i<100001; i++) {
    dp[i]=max(dp[i-1],dp[i-2]+arr[i]*i);
}
cout << dp[100000] << endl;
}