import java.util.*;

public class Replace {

	public static void main(String[] args) {
		String test = "hello";
		
		String outString = replaceAll(test, 'l', 'm');
		
		System.out.println(outString);
		

	}
	
	public static String replaceAll(String s, char target, char newChar) {
		for (int i= 0; i < s.length(); i++) {
			if (s.charAt(i) == target) {
				s = s.substring(0, i) + newChar + s.substring(i+1);
			}
		}
		return s;
	}

}