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A9166 | Magic Numbers

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内存限制256MB
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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.

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
C++ 编辑器
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