import sys


def _solve(A, B):
    return 50 * A + int((500 * A) // (8 + 2 * B))


def solve(in_):
    A, B = map(int, next(in_).split())
    return _solve(A, B)
    

def main():
    answer = solve(sys.stdin.buffer)
    print(answer)


if __name__ == '__main__':
    main()