A = int(input())
N = 2
M = 1
x = N
while x < A:
    M += 1
    x *= N
ans = N * M
M = 2
N = int(A ** 0.5)
while N * N < A:
    N += 1
ans = min(ans, N * M)
N = 3
M = 1
x = N
while x < A:
    M += 1
    x *= N
ans = min(ans, N * M)
M = 3
N = int(A ** 0.333333)
while N * N < A:
    N += 1
ans = min(ans, N * M)
print(ans)