#include <cstdio>
#include <iostream>

using namespace std;
int a,b,c,d,e,f;
int fo(int n,int k){
	return 50*n+(int)(50*n/(0.8+0.2*k));
}

int main(){
	int a,b;
	cin>>a>>b;
	printf("%d\n",fo(a,b));
}