#include <stdio.h>
#include <algorithm>
#include <vector>
#include <deque>
#include <string>
#include <iostream>
using namespace std;
using ll = long long;

void solve();
int main() {
	solve();
#ifdef DBG
	while (true);
#endif
}

//445
void solve() {
	int a, b;
	scanf("%d %d", &a, &b);
	printf("%d\n", (50 * a) + (500 * a / (8 + 2 * b)));
}