N=int(input())
ans=int(1e100)
for i in range(100):
    x=pow(N,-1-i)
    x=int(x)
    if(x**(i+1)>N):
        ans=min(ans,x*(i+1))
    x+=1
    if(x**(i+1)>N):
        ans=min(ans,x*(i+1))
print(ans)