#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<math.h>
#include<map>
#include<iomanip>
#include<queue>

const long long INF = 1e6+7;
const long long MOD = 1e9+7;
const double PI=acos(-1);

using namespace std;

double func(int n,int k){
	int result;
	result=50*n+(50*n)/(0.8+0.2*(double)k);
	return result;
}

int main(){
	int a,b;
	cin >> a >> b;
	int ans=func(a,b);
	cout << ans << endl;
}