A. Chat room
time limit per test1 second
memory limit per test256 megabytes
inputstandard input
outputstandard output
Vasya has recently learned to type and log on to the Internet. He immediately entered a chat room and decided to say hello to everybody. Vasya typed the word s. It is considered that Vasya managed to say hello if several letters can be deleted from the typed word so that it resulted in the word “hello”. For example, if Vasya types the word “ahhellllloou”, it will be considered that he said hello, and if he types “hlelo”, it will be considered that Vasya got misunderstood and he didn’t manage to say hello. Determine whether Vasya managed to say hello by the given word s.
Input
The first and only line contains the word s, which Vasya typed. This word consisits of small Latin letters, its length is no less that 1 and no more than 100 letters.
Output
If Vasya managed to say hello, print “YES”, otherwise print “NO”.
Examples
inputCopy
ahhellllloou
outputCopy
YES
inputCopy
hlelo
outputCopy
NO
题解：先开始想的是暴力思路进行求解或者字符串匹配，但是这种五重循环进行暴力求解，对于此时的字符串的长度是100的数据是会超时的；五重循环此时是不行的。字符串匹配用来解这种有点得不偿失。我们可以对于字符串进行一次扫描，我们可以进行采取一个标志数字进行字符串的匹配，对于目标子串的每一个字符进行匹配，如果是顺序的目标字符则转移下一个状态，否则保持当前状态不变，如果扫描完给定的字符串，那么对于是否进行了最后一个状态进行判断，符合则YES，反之NO。
