/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{  System.out.println(replaceCharacter("This is the letter i", 'i', "east"));
    }
 
    public static String replaceCharacter(String w, char b, String v) {
        String result = "";
        for (int i = 0; i < w.length(); i++) {
            if (w.charAt(i) == b) {
                result += v;
            } else {
                result += w.charAt(i);
            }
        }
        return result;
    }
}

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