Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 342001    Accepted Submission(s): 86236

Problem Description

Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).

In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

 

 

Input

The input will consist of a series of integers n, one integer per line.

 

 

Output

For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

 

 

Sample Input

1 100

 

 

Sample Output

1 5050

 题意：求1到n的和

#include
      
       using namespace std;int main(){    int a,b,c;    while(cin>>a){        c=0;        for(b=1;b<=a;b++)            c+=b;        cout<
       
        <
        
         <