A special number PTA 7-2 column sum string (20 minutes)

#include<stdio.h>

int main()
{
    int m, n;
    int sum = 0;
    int he = 0;
    scanf("%d %d", &m, &n);
    for (int i = 0; i < n; i++)
    {
        sum = sum * 10 + m;
        he += sum;
    }
    printf("s = %d", he);
}