print('生物 world!')
def mylog(A,B,C):
    D=(0.1)**C
    k = [1,0,10**(1/2**B)]
    while(k[0] < A):
        k[0] *= k[-1]
        k[1] += (1/2**B)
    if (10**k[0] > A):
        return (((k[1]-(1/2**B))/(D))-(((k[1]-(1/2**B))/(D))%1))*(D)
    else:
        return (((k[1])/(D))-(((k[1])/(D))%1))*(D)
print(mylog(2,25,5))