#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    float money = 0;
    for (int i = 0; i < n; ++i) {
        int count;
        cin >> count;
        money += count / 70 * 0.1;
        if (count % 70 > 0) money += 0.1;
    }
    cout << money << endl;
    return 0;
}