What is wrong in the code

#1
#2

Here is the corrected code :

import java.util.Scanner;

public class replacePi {
static int m, n;

public static void main(String[] args) {

	Scanner obj = new Scanner(System.in);
	int n = obj.nextInt();
	for (int i = 0; i < n; i++) {
		String s = obj.next();
		replace(s, 0, "");
	}

}

public static void replace(String s, int si, String ns) {

	if (si == s.length()) {
		System.out.println(ns);
		return;
	}
	if (s.charAt(si) == 'p' && s.charAt(si + 1) == 'i') {
		ns = ns + "3.14";
		replace(s, si + 2, ns);
	} else {
		ns = ns + s.charAt(si);
		replace(s, si + 1, ns);
	}

}

}