n, w = map(int, input().split())
V, W = [], []
for i in range(n):
    vv, ww = map(int, input().split())
    V.append(vv)
    W.append(ww)
ans = -1
for i in range(n):
    if W[i] <= w:
        ans = max(ans, V[i])
print(ans)