C :

#include<stdio.h>
#include<string.h>
#include<math.h>
int main()
{
  int n,i,j,k,len;
  char  a[105],b[205],c[105],d[20]="ENDOFINPUT";
  for(i=0;;i++)
  {
	  len=0;
	  gets(a);
	  if(strcmp(a,d)==0)  return 0;
	  gets(b);
	  len=strlen(b);
	  gets(c);
	  for(j=0;j<len;j++)
	 { if(b[j]>='A'&&b[j]<='E') b[j]=b[j]+21;
	  else if(b[j]>='F'&&b[j]<='Z')  b[j]=b[j]-5;}
	puts(b);
	
  }
  return 0;


}

Java :

import java.util.Scanner;

public class Main {
	public static void main(String args[]) throws Exception {
		Scanner sc = new Scanner(System.in);
		String startFlag = "";
		String endFlag = "";
		int len = 0;
		char[] array;
		while (sc.hasNext()) {
			startFlag = sc.nextLine();
			if ("START".equals(startFlag)) {
				array = sc.nextLine().toCharArray();
				len = array.length;
				for (int i = 0; i < len; i++) {
					if (array[i]>='A' && array[i] <= 'E') {
						array[i] = (char) (array[i] + 'v' - 'a');
					}else if (array[i]>='F' && array[i] <= 'Z') {
						array[i] = (char) (array[i] - 5);
					}
					System.out.print(array[i]);
				}
				System.out.println();
				endFlag = sc.nextLine();
			} else if ("ENDOFINPUT".equals(startFlag)) {
				break;
			}
		}
	}
}