Magic Numbers
题目描述
A. Magic Numbers
time limit per test
2 secondsmemory limit per test
256 megabytesinput
standard inputoutput
standard outputA 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.
Input
The first line of input contains an integer n, (1≤n≤109). This number doesn't contain leading zeros.
Output
Print "YES" if n is a magic number or print "NO" if it's not.
Examples
Input
114114
Output
YES
Input
1111
Output
YES
Input
441231
Output
NO
题目来源：fps-www.educg.net-codeforce-1-2833.xml.zip；FPS 共享题包，题包内第 2021 题。保留原作者与原赛事署名。