import sys
input = lambda : sys.stdin.readline().rstrip()
sys.setrecursionlimit(max(1000, 10**9))
write = lambda x: sys.stdout.write(x+"\n")


# inputna
n,m = list(map(int, input().split()))
tp = [list(map(int, input().split())) for _ in range(m)]
tp.sort()
c = 0
ct = 0
for t,p in tp:
    if abs(c-p)>t-ct:
        ans = False
        break
    c = p
    ct = t
else:
    ans = True
if ans:
    print("Yes")
else:
    print("No")