#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];
}
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