程序代码：

#include <iostream>
using namespace std;

int main(void)
{
    int n;
    while (cin >> n)
    {
        int sum=0;
        int num=0;
        for (int i=1; i<=n; i++)
        {
            num=num*10+i;
            sum+=num;
        }
        cout<<sum<<endl;
    }

    return 0;
}