N=int(input())
ans=int(1e100)
for i in range(100):
    if i==0:
        continue
    x=pow(N,1/i)
    x=int(x)
    #print(x**i)
    if(x**i>N):
        ans=min(ans,x*i)
    for j in range(10000):
        x+=1
        if(x**i>N):
            ans=min(ans,x*i)
print(ans)