#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 2000000005


int main(){
	
	long long A;
	cin>>A;
	long long ret = 10000;
	for(long long i=2;i<=100;i++){
		long long now = 1;
		long long ans = 0;
		while(now<A){
			now *= i;
			ans += i;
			if(ans>=ret)break;
		}
		
		ret = min(ret,ans);
	}
	
	cout<<ret<<endl;
	
	return 0;
}