#include <bits/stdc++.h>
using namespace std;
#define N_PRIME 1000000007
#define ll int64_t

int f(int n,int k){
    return 50 * n + int(250 * n/(4+k));
}

int main(void){
    int A,B;
    cin >> A >> B;
    cout << f(A,B) << endl;
    return 0;
}