#include <stdio.h>

int sum(int m, int n)
{
    int i;
    int sum = 0;
    for ( i = m; i <=n; i++)
    {
        sum += i;
    }
    return sum;

}

int main()
{    
    int m, n;
    printf("输入m和n：\n");
    scanf("%d,%d", &m, &n);
    printf("sum = %d\n", sum(m, n));    
    return 0;
}