#include <iostream>
using namespace std;
int Fun(int x){
	if(x<1)
		return x;
	if(x>=1&&x<10)
		return 2*x-1;
	if(x>=10)
		return 3*x-11;
}
int main() {
	int n;
	while(cin>>n)
		cout<<Fun(n)<<endl;
	return 0;
}