from decimal import *

def solve():
    getcontext().prec = 25
    a, b = input().split()
    a, b = max(a, b), min(a, b)
    print(Decimal(Decimal(a) ** Decimal(2) - Decimal(b) ** Decimal(2)) ** Decimal(0.5))

if __name__=="__main__":
    solve()