A9166. Magic Numbers
编程题
普及/提高-
知识点
题目描述
A magic number is a number formed by concatenation of numbers $1$ , $14$ and $144$ . We can use each of these numbers any number of times. Therefore $14144$ , $141414$ and $1411$ are magic numbers but $1444$ , $514$ and $414$ are not.
You're given a number. Determine if it is a magic number or not.
You're given a number. Determine if it is a magic number or not.
输入格式
The first line of input contains an integer $n$ , $(1<=n<=10^{9})$ . This number doesn't contain leading zeros.
输出格式
Print "YES" if $n$ is a magic number or print "NO" if it's not.
输入输出样例
输入 #1
114114
输出 #1
YES
输入 #2
1111
输出 #2
YES
输入 #3
441231
输出 #3
NO