import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*; import java.util.stream.*; public class Solution { public static void main(String[] args) { Scanner in = new Scanner(System.in); int q = in.nextInt(); for(int a0 = 0; a0 < q; a0++){ int len = in.nextInt(); int c = in.nextInt(); int maxComps = IntStream.range(1,len).sum(); if(c > maxComps) { System.out.println("-1"); continue; } } } }