public class StringCounter {

	public static void main(String[] args) {
		
		if (args!=null) {
			StringCounter stringCounter= new StringCounter();
			System.out.println(stringCounter.incrementString(args[0])); 
		} else {
			System.out.println("usage: java StringCounter <character>");
		}
		
	}
	
	String incrementString(String string) {
		char[] cArray = string.toCharArray();
			
		for (int n = 1; n < cArray.length+1; n++) {
			
			// 122 upperbound , equals to "z" in java Primitive character types
			if (cArray[cArray.length-n]==122) {
				
				// if necessarry, add digit
				if (cArray.length-n==0) {
					// increment array size
					cArray= new char[cArray.length+1];
					// reset counter lowest bound , eg. aaa
					for (int i = 0; i < cArray.length; i++) {
						// 97 lowerbound , equals to "a" in java Primitive character types
						cArray[i]=97;
					}
					break;
				} else {
					cArray[cArray.length-n]=97;
				}
				
			} else {
					++cArray[cArray.length-n];
					break;
			}
		}
		
		return String.valueOf(cArray);
	}

}