#include <iostream>

using namespace std;
int main() {
	int n;
	cin>>n;
	int* arr = new int[n]; 
	int* freq = new int[100001]();
    for(int i = 0;  i<n; ++i) {
	cin>>arr[i];
	freq[arr[i]]++;
}
int* dp = new int[100001]();
dp[0] = 0;
dp[1] = freq[1];
   for(int i = 2; i<=100001; i++) {
   	dp[i] = max(dp[i-1], dp[i-2] + i*freq[i]);
   	
   }
	
 	cout<<dp[100001];
	
	
	
	
	
	
}