SP15165 PTR2 - primes triangle (II)

Primes triangle is a triangle that contain all prime numbers. ```           2        3 5       7 11 13     17 19 23 29   ... ... ... ``` Your task is very easy given an integer from 1 to 10^9 prints its place in the primes triangle .

in the first line integer 1

one line contain pair of integers i, j .where i is the row number and j is the column number, 1 base. or -1 if n not exist in the primes triangle.