n = int(input())
p = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113]
ans = 200
for x in p:
    y = 1
    cnt = 0
    while y < n:
        y *= x
        cnt += 1
    ans = min(ans, x*cnt)
print(ans)