#include<bits/stdc++.h>
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3f
#define EPS (1e-10)
#define rep(i,n)for(int i=0;i<n;i++)
#define sqrt(s)sqrt(max(0.0,s))
using namespace std;
typedef long long ll;
typedef pair<int, int>P;

int main() {
	int n, k; cin >> n >> k;
	cout << 50 * n + floor(50 * n / (0.8 + 0.2*k)) << endl;
}