#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    int32_t a, b;
    cin >> a >> b;
    cout << 50 * a + int32_t(500 * a / (8 + 2 * b)) << endl;
    return 0;
}