#include <bits/stdc++.h>

using namespace std;

int32_t main() {
    double p, q, ans = 0;
    cin >> p >> q;
    int n;
    cin >> n;
    while(n--){
        int x; cin >> x;
        double pr_ans = x;
        pr_ans += max(q, floor(p * x) / 100);
        ans += pr_ans;
    }
    cout.precision(2);
    cout << fixed << ans << '\n';
}