from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    N, M = map(int, input().split())
    TP = [tuple(map(int, input().split())) for _ in [0] * M]

    t_, p_ = 0, 0
    for t, p in TP:
        if t - t_ <= abs(p - p_):
            print("No")
            break
        t_, p_ = t, p
    else:
        print("Yes")


main()