Problem 1001: Sum Problem

Thanks to drizzlecrj's suggestion, I turned to hdu for the primary practice. Hnu was another choice, but the server is too poor that a submitted problem is showed "wariting" all the time.

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

  
    

   
     
   
     #include 
   
     <
   
     stdio.h
   
     >
   
     


   
     int
   
      main()

   
     
   
     {
    int a = 0, b = 0;
    while(scanf("%d", &a) != EOF)
    {
        b = 0;
        int i = 1;
        for(; i <= a; i++)
            b = b + i;
        printf("%d\n\n", b);
    }
    return 0;
}
  
    

Summary:
Easy as it may seem, I am starting off.