#yuki1205
n,m=map(int,input().split())
l=[]
for i in range(m):
 t,p=map(int,input().split())
 l.append([t,p])
t0,p0=0,0
for i in range(m):
 if l[i][0]-t0<abs(l[i][1]-p0):
  exit(print('No'))
 t0,p0=l[i][0],l[i][1]
print('Yes')