N,M=map(int,input().split())
z=[list(map(int,input().split())) for _ in range(M)]
z=sorted(z)
s='No'
t0,p0=0,0
for t,p in z:
    if t-t0<p-p0:   break
    t0,p0=t,p
else:   s='Yes'
print(s)