def get_divs(l):
divs = set([1])
for i in xrange(1, len(l) + 1):
for j in list(ce(l, i)):
divs.add(reduce(lambda x, y: x * y, j))
for i in divs:
print i,
def get_divs(l):
divs = set([1])
for i in xrange(1, len(l) + 1):
for j in list(ce(l, i)):
divs.add(reduce(lambda x, y: x * y, j))
for i in divs:
print i,
def solve(d, s):
if len(d) == 1:
return 0
maxLen = 0
for i in ce(d.iterkeys(), len(d) - 2):
L = [k for k in s if k not in i]
if isValidString(L):
maxLen = max(maxLen, len(L))
return maxLen
def combine_with_rep(string, num):
for j in ce(sorted(string), num):
print(''.join(j))
saved[1] = en
yield saved[1] - saved[0]
if __name__ == '__main__':
from itertools import combinations as ce
for _ in xrange(input()):
N, L = map(int, raw_input().split())
roads = []
for _ in xrange(N):
a, b = map(int, raw_input().split())
roads.append((a, b))
found = False
for i in xrange(1, N + 1):
for subRoad in ce(roads, i):
if i == 1:
# subroad must be a single interval
if subRoad[0][1] - subRoad[0][0] == L:
found = True
break
for roadLength in merge(subRoad):
if roadLength == L:
found = True
break
if found:
break
if found:
break