// DP practice
// 455A --- codeforces
#include <iostream>
#include <stdio.h>
#include <cstring>
using namespace std;
const int N = 1000010;
long long int dp[N];
long long int cnt[N];
int main()
{
int iT;
int iNum,iLarge;
int i,j;
cin >> iT;
memset(cnt,0,sizeof(cnt));
iLarge = 0;
for ( i=0 ; i<iT ; i++ )
    {
    cin >> iNum;
    // count number appear times
    cnt [iNum]++;
    // store the largest number to reduce run time
    if ( iNum>iLarge )
        iLarge = iNum;
    }
dp[0] = 0;
dp[1] = cnt[1];
for ( j=2 ; j<=iLarge ; j++ )
    dp[j] = max(dp[j-1],dp[j-2] + (cnt[j]*j));

cout << dp[j-1] << endl;
}