#include<bits/stdc++.h>
using namespace std;
int a,s;
int f(int n){
	int r;
	if(n==1) r=a;
	else r=f(n-1)*10+a;
	return r;
} 
int main(){
	cin>>a;
	for(int i=1;i<=a;i++){
		s=s+f(i); 
	}
 cout<<s;
 
	return 0;
}

/**************************************************************
	Problem: 1245
	User: huxuanchen
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/