from sys import setrecursionlimit, stdin
from collections import defaultdict, deque
from itertools import permutations, combinations, product
from functools import lru_cache
from random import sample, choice, randint, random
from heapq import heappush, heappop
from math import factorial, gcd, exp
from copy import copy, deepcopy
from time import time
setrecursionlimit(10 ** 6)
readline = stdin.readline
# @lru_cache(maxsize=None)
INF = 10 ** 18
MOD = 1000000007
# MOD = 998244353
DYDX = [(-1, 0), (1, 0), (0, -1), (0, 1)]
def I(): return int(readline())
def S(): return readline()[:-1]
def LI(): return list(map(int, readline().split()))
def SPI(): return map(int, readline().split())
def SPII(): return map(lambda x: int(x)-1, readline().split())
def FIE(x): return [readline()[:-1] for _ in [0] * x]
def NODE(x): return [[] for _ in [0] * x]
def ranges(*args): return [(i, j) for i in range(args[0]) for j in range(args[-1])]
def nynx(y, x, ly = INF, lx = INF): return [(y+dy, x+dx) for dy, dx in DYDX if 0 <= y+dy < ly and 0 <= x+dx < lx]
def imax(A, idx=-1, m=-(1<<18)):
    for i, a in enumerate(A): m, idx = [[m, idx], [a, i]][m < a]
    return idx
def imin(A, idx=-1, m=1<<18):
    for i, a in enumerate(A): m, idx = [[m, idx], [a, i]][m > a]
    return idx
def cmin(dp, i, x):
    if x < dp[i]: dp[i] = x
def cmax(dp, i, x):
    if x > dp[i]: dp[i] = x
def gen(x, *args):
    ret = [x] * args[-1]
    for e in args[:-1][::-1]: ret = [deepcopy(ret) for _ in [0] * e]
    return ret
def puts(E):
    for e in E: print(e)
def pprint(E): 
    print()
    puts(E)
####################################################################

A = I()
# N ** M >= A
limit = 10 ** 6
ans = INF
for N in range(2, limit+1):
    for M in range(1, limit+1):
        e = N ** M 
        if e >= A:
            ans = min(ans, N*M)
            break

print(ans)