BOJ1010 다리 놓기

import math

for _ in range(int(input())):
	R, N = map(int, input().split())

	if N == R:
		print(1)
		continue
	else:
		
		# nCr = nCn-r
		r = N-R if N-R < R else R

		# nCr = nPr // r!
		nPr = 1
		for i in range(N, N-r, -1):
			nPr *= i
		facto_r = math.factorial(r)

		print(nPr // facto_r)