#include <iostream>
using namespace std;

int main() {

    // write your code here......
    long long sum = 0;
    int i = 1;
    long long n = 0;
    while(i<=10)
    {
        n = 9 + n*10;
        sum = sum + n;
        i++;
    }
    printf("%lld",sum);
    return 0;
}