import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

n, m = MI()
c = 0
ct = 0
ans = "Yes"

for i in range(m):
    t, p = MI()
    if abs(c-p) <= t-ct:
        cp = p
        ct = t
    else:
        ans = "No"

print(ans)