#include<iostream>
#include<string>
#include<algorithm>
#include<functional>
#include<vector>
#include<set>
#include<queue>
#include<list>
#include<stdio.h>
#include<stdlib.h>
#include<map>

#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()

typedef long long ll;

using namespace std;

int main() {
	int A, B;

	cin >> A >> B;

	int first = 50 * A;
	int second = 8 + 2 * B;

	int third = 500 * A;

	int ans = first + third/second;

	cout << ans << endl;
}