n balls with different rays
Source: Moldova TST, day 2, problem B8
March 26, 2016
combinatorics
Problem Statement
Let us have ( ) balls with different rays. On each ball it is written an integer number. Determine the greatest natural number such that for any numbers written on the balls, we can always find at least 4 different ways to choose some balls with the sum of the numbers written on them divisible by .