from decimal import Decimal
import sys


def input(): return sys.stdin.readline().rstrip('\n')


def f(n, k):
    return 50 * n + int(50*n/(Decimal('0.8') + Decimal('0.2')*k))


def main():
    a, b = map(int, input().split())
    print(f(a, b))


if __name__ == '__main__':
    main()