**Problem:** Given n (n<=100) integers a[i] (1<=i<=n && 1<=a[i]<=1 billion). Find all m>1 satisfying:

a[1] % m = a[2] % m = a[3] % m = … = a[n] % m.

**Input:** `n and n integers a[i]`

**Output:** all possible m (all input will have a solution)

Please help me on this problem!