10分钟完成此题

#include<iostream>
using namespace std;
int main()
{
    //freopen("xxx.in","r",stdin);
    //freopen("yyy.out","w",stdout);
    int A,N;
    cin >> A >> N;
    int sum=A;
        while(N<=0)
            cin >> N;
    for(int i=1;i<N;i++)
        sum=sum+(A+i);
    cout << sum;
    //fclose(stdin);
    //fclose(stdout);
    return 0;
}