#include <bits/stdc++.h>
#define INF 990000000
//14
using namespace std;

int main() {

double dat,n;

cin>>n;

dat=1.5*n;

for(int i=1;i<n*1.5+1;i++){
if(dat-(double)i<1.0){
cout<< i<<endl;
break;
}
}


}