The task is to generate the correct answer for a given math problem.

Input: Consider Input: Problem: if each participant of a chess tournament plays exactly one game with each of the remaining participants , then 153 games will be played during the tournament . find the number of participants .

Output: 18


Input: Consider Input: Problem: what is the total number of integers between 10 and 50 that are divisible by 2 ?

Output: 19


Input: Consider Input: Problem: a is two years older than b who is twice as old as c . if the total of the ages of a , b and c be 17 , the how old is b ? a . 7 b . 8 c . 9 d . 10 explanation :


Output: 6