#include<bits/stdc++.h>
#define ll long long
#define N_max 1e6  
using namespace std ;
ll n , cnt , ma ;
ll a[int(1e6)] , f[int(1e6)] , dau[int(1e6)];
int main(){
    ios_base::sync_with_stdio(0);
	cin.tie(0) ;   cout.tie(0);
	cin >> n ;
 
	for ( ll i = 1 ; i <= n ; i++ ){
		cin >> a[i] ;
		dau[a[i]] ++ ;
		ma = max(ma,a[i]) ;
	}
 
	f[1] = dau[1] ;
	for ( ll i = 1 ; i <= ma ; i++ )
		f[i] = max ( f[i-1] , f[i-2] + dau[i]*i ) ;
 
	cout << f[ma] ;
 
}
 

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