#include <stdio.h>

int sum(int n){
	int i;
	int sum;
	int num;
	for(i=0;i<=n;i++){
		sum = sum + num;
		num = num*10 + n;
	}
	return n;
}

int main(void){
	int i = 4;
	printf("%d",sum(4));
	return 0;
}