Sum from 1 to N
Add up every integer from 1 to N with a loop.
Input format
One line with an integer N (at least 1).
Output format
Print the sum 1 + 2 + ... + N.
Constraints
- Values fit in a 64-bit signed integer
- Trailing whitespace and a trailing newline are ignored by the judge
Read from stdin, write to stdout. Sample cases below show the exact format.
Sample cases
Example 1
Input
5Expected output
15Example 2
Input
10Expected output
55