#include<bits/stdc++.h>
using namespace std;
int n,answer; 
int dg(int y){
	if(y==1) return n;
	else return (y-1)*10+n;
}


int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		answer+=dg(i);	
	}
	cout<<answer;

	return 0;
}

/**************************************************************
	Problem: 1245
	User: hongjiaming
	Language: C++
	Result: Wrong Answer
****************************************************************/