a = int(input())

tmp =[]

#m=2のときは別途
l = 1
r = 10**9
while r - l > 1:
  c = (l+r)//2
  if c**2 <= a:
    l = c
  else:
    r = c
tmp.append(r*2)

#m=3のときは別途
l = 1
r = 10**6
while r - l > 1:
  c = (l+r)//2
  if c**3 <= a:
    l = c
  else:
    r = c
tmp.append(r*3)

n = 2
for m in range(70, 3, -1):
  while n**m <= a:
    n += 1
  tmp.append(n*m)
  n -= 1

# m=1のときはn=a+1になる。これも忘れずに。
print(min(min(tmp), a+1))