#include <stdio.h> #include <stdlib.h> int main(void) { int N = 0; scanf("%d", &N); for (int i = 0; i < N; i++) { int card = 0, result = 0, originRes = 0; scanf("%d %d", &card, &result); for (int i = 1; i <= card; i++) { originRes += i; } if (originRes == result) { printf("YES\n"); } else { printf("NO\n"); } } return 0; }