#include<bits/stdc++.h>
#define ll long long
#define endl "\n"
#define F first
#define S second
#define loop(a,n) for(int i=a; i<=n ; i++)
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define NAME ""
using namespace std;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
//freopen(NAME".INP","r",stdin);
//freopen(NAME".OUT","w",stdout);
int n,a,b,c;
cin>>n;
if(n<5) cout<<2;
else {
a=2,b=3,c=a;
while(a<=n) {
c=a;
a+=b;
b*=3;
}
cout<<c;
}
return 0;
}
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