def main():
    N, M = map(int, input().split())
    current_position = 0
    current_time = 0
    information = [list(map(int, input().split())) for _ in range(M)]
    for T, P in information:
        if (T - current_time) < abs(P-current_position):
            print("No")
            return
        current_position = P
        current_time = T
    print("Yes")


if __name__ == "__main__":
    main()