# -*- coding: utf-8 -*-
"""
No.445 得点
https://yukicoder.me/problems/no/445

"""
import sys
from sys import stdin
input = stdin.readline


def solve(N, K):
    return int(50 * N + (50 * N) / (0.8 + 0.2*K))


def main(args):
    A, B = map(int, input().split())
    ans = solve(A, B)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])