from math import floor


def calc_short_degree(hour, minute, second) -> int:
    return (hour * 30) % 360 + minute/2 + second/120


def calc_long_degree(minute, second) -> int:
    return minute * 6 + second / 10


def main():
    until_zero_minute_time = 0
    A, B = map(int, input().split())
    long_degree = calc_long_degree(B, 0)
    short_degree = calc_short_degree(A, B, 0)
    if long_degree == short_degree:
        print(0)
        return

    if long_degree > short_degree:
        until_zero_minute_time = (60 - B) * 60
        long_degree = 0
        short_degree = (A+1, 0, 0)
        B = 0
        A += 1

    for time in range(1, 3601):
        long_degree = calc_long_degree(B + time // 60, time % 60)
        short_degree = calc_short_degree(A, B + time // 60, time % 60)
        if long_degree > short_degree:
            print(until_zero_minute_time + time - 1)
            return
        if long_degree == short_degree:
            print(until_zero_minute_time + time)
            return
    raise ValueError


if __name__ == "__main__":
    main()