n, w = map(int, input().split())
assert(1 <= n <= 1000)
assert(1 <= w <= 1000)
V = [0] * n
W = [0] * n
for i in range(n):
	V[i], W[i] = map(int, input().split())
	assert(1 <= V[i] <= 1000)
	assert(1 <= W[i] <= 1000)
maxw = 0
ans = -1
for i in range(n):
	if W[i] <= w:
		maxw = W[i]
		ans = max(ans, V[i])
print(ans)