Problem:
Score : 200 points

Problem Statement

A string is called a KEYENCE string when it can be changed to keyence by removing its contiguous substring (possibly empty) only once.

Given a string S consisting of lowercase English letters, determine if S is a KEYENCE string.

Constraints

The length of S is between 7 and 100 (inclusive).

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is a KEYENCE string, print YES; otherwise, print NO.

Sample Input 1

keyofscience

Sample Output 1

YES

keyence is an abbreviation of key of science.

Sample Input 2

mpyszsbznf

Sample Output 2

NO

Sample Input 3

ashlfyha

Sample Output 3

NO

Sample Input 4

keyence

Sample Output 4

YES

Solution in JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
	input = input.trim();
  var key = "keyence";
 var list = [key,["k","eyence"],["ke","yence"],["key","ence"],
             ["keye","nce"],["keyen","ce"],["keyenc","e"]];
  for(var i = 0; i < list.length; i++){
    if(i == 0){
      if(input.indexOf(key) != -1){
     	  input = input.split(key);
      	if(input[0] != "" && input[1] != ""){
       	  console.log("NO");
      	}else{
       	   console.log("YES");
     	 }
      	return;
    	}else{
         continue; 
        }
    }else{
      var firstCheck = "";
      var secondCheck = "";
      if(list[i][0].length > list[i][1].length){
         firstCheck = list[i][0];
      	 secondCheck = list[i][1];
      }else{
           firstCheck = list[i][1];
      	 secondCheck = list[i][0];
      }
      //console.log(list[i]);
      if(input.indexOf(firstCheck) != -1){
         input = input.split(firstCheck);
        
        if(input[0] == "" || input[1] == ""){
          input = input.join("").split(secondCheck);
          //console.log(input);
          if(input[0] == "" || input[1] == ""){
           console.log("YES");
          }else{
            console.log("NO");
          }
        }else{
          console.log("NO");
        }
        return;
      }else{
           continue;
      }
    }
  }
  console.log("NO");
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));