1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 inline ll read(){
 5     int x=0,f=1;char ch=getchar();
 6     while(ch>‘9‘||ch<‘0‘){if(ch==‘-‘)f=-1;ch=getchar();}
 7     while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
 8     return x*f;
 9 }
10 
11 /***********************************************************/
12 
13 const int maxn = 1e5+7;
14 ll a[maxn];
15 
16 void init(){
17     for(ll i = 1;i <= 15;i++){
18         a[i] = 1;
19         for(ll j = 1;j <= i;j++){
20             a[i] *= i;
21         }
22         //cout << i << " :" << a[i] << endl;
23     }
24 }
25 
26 
27 int main(){
28     init();
29     ll n;
30     while(~scanf("%lld", &n)){
31         int ans = 0;
32         for(ll i = 1;i <= 15;i++){
33             if(n >= a[i])
34                 ans++;
35             else break;
36         }
37         cout << ans << endl;
38     }
39     return 0;
40 }