n,w=list(map(int,input().split()))
a_list=sorted([list(map(int,input().split())) for _ in range(n)], key=lambda x:x[0],reverse=True)
a_list=[a for a in a_list if a[1]<=w]
print (a_list)
if len(a_list)==0:
    print(-1)
else:
    print(a_list[0][0])