В IDEA всё работает.
package com.javarush.task.task04.task0417;
import java.util.Scanner;
/*
Существует ли пара?
*/
public class Solution {
public static void main(String[] args) throws Exception {
Scanner in = new Scanner(System.in);
int a = in.nextInt();
int b = in.nextInt();
int c = in.nextInt();
if (a == b)
System.out.print(a + " " + b + " ");
else {
if (b == c)
System.out.print(b + " " + c);
}
if (a == b & b == c)
System.out.print(c);
else
System.out.print("");
}
}