N,M=map(int,input().split())
data=[0,0]
import math
memo=0
for i in range(M):
    T,P=map(int,input().split())
    T_p=data[0]
    P_p=data[1]
    if int(math.fabs(T_p-T))>=int(math.fabs(P_p-P)):
        data=[T,P]
    else:
        memo+=1
        break
if memo==0:
    print("Yes")
else:
    print("No")