n, m = map(int, input().split())
t, p = [0], [0]

for i in range(m):
    ti, pi = map(int, input().split())
    t.append(ti)
    p.append(pi)

ans = "Yes"
for i in range(len(t) - 1):
    if t[i + 1] - t[i] < abs(p[i + 1] - p[i]):
        ans = "No"

print(ans)