n = int(input())

def jiechen(x):

if x==1:
    return 1
else:
    return x*jiechen(x-1)

s = jiechen(n)

s = list(str(s))

l = len(s)

for i in range(l):

if s[l-1-i]!="0":
    print(s[l-1-i])
    break