判断IP地址合法性

ip = input()
ip = ip.split('.')    
if len(ip) == 4:   
    for i in range(4):         
        if ip[i].isdigit() == False or  eval(ip[i]) > 255 or eval(ip[i]) < 0:  
            print('No')
            break     
    else: 
        if i == 3:   
            print('Yes')
else:
    print('No')