N, M = map(int, input().split())

TP = [[0, 0]] + [list(map(int, input().split())) for i in range(M)]

for i in range(1, M + 1):
    
    if TP[i][0] - TP[i - 1][0] < abs(TP[i][1] - TP[i - 1][1]):
        
        print('No')
        exit()
        
print('Yes')