题目描述

#include <iostream>
using namespace std;
int main()
{
    int a, b, sum = 0;
    cin >> a;
    while(cin >>  b, b <= 0);//for循环不需要在while循环内

    for (int i = 0; i < b; i ++) sum += a + i;

    cout << sum << endl;
    return 0;
}