#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <iomanip>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

#define FOR(i,a,b) for(ll i = (a);i<(b);i++)
#define REP(i,a) FOR(i,0,(a))
#define MP make_pair

int getAns(int n, int k){
	return 50 * n + ((500 * n) / (8 + 2 * k));
}

int main() {
	int n,k;
	cin >> n >> k;

	cout << getAns(n, k) << endl;
	return 0;
}