N, M, *TP = map(int, open(0).read().split())
TP = [(0, 0)] + list(zip(*[iter(TP)] * 2))

if all(t2 - t1 >= abs(p2 - p1) for (t1, p1), (t2, p2) in zip(TP, TP[1:])):
    print("Yes")
else:
    print("No")