#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
if (!(cin >> n)) return 0;
const int MAXV = 100000;
vector<long long> cnt(MAXV + 1, 0);
int x;
int maxv = 0;
for (int i = 0; i < n; ++i) {
cin >> x;
if (x >= 0 && x <= MAXV) {
cnt[x]++;
if (x > maxv) maxv = x;
}
}
if (maxv == 0) {
cout << 0 << '\n';
return 0;
}
vector<long long> dp(maxv + 1, 0);
dp[0] = 0;
dp[1] = cnt[1] * 1LL;
for (int v = 2; v <= maxv; ++v) {
dp[v] = max(dp[v-1], dp[v-2] + cnt[v] * 1LL * v);
}
cout << dp[maxv] << '\n';
return 0;
}
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