N, M = map(int, input().split())
T = []
P = []

for i in range(M):
    T_add, P_add = map(int, input().split())
    T.append(T_add)
    P.append(P_add)

P_now = 0
ans = 'Yes'
for M_now in range(M):
    if abs(P[M_now]-P_now) > T[M_now]:
        ans = 'No'
        break
    now = P[M_now]
print(ans)