Dado un número x, encuentre y tal que x*y + 1 no sea un número primo

Dado un número x, encuentre y (y > 0) tal que x*y + 1 no sea un número primo.
Ejemplos: 
 

Input : 2
Output : 4

Input : 5
Output : 3

Observación: 
 

x*(x-2) + 1 = (x-1)^2 que no es primo. 
 

Acercarse : 

For x > 2, y will be x-2 otherwise y will be x+2

#include <bits/stdc++.h>
using namespace std;
 
int findY(int x)
{
    if (x > 2)
        return x - 2;
 
    return x + 2;
}
 
// Driver code
int main()
{
    int x = 5;
    cout << findY(x);
    return 0;
}

#include <stdio.h>
 
int findY(int x)
{
    if (x > 2)
        return x - 2;
  
    return x + 2;
}
  
// Driver code
int main()
{
    int x = 5;
    printf("%d",findY(x));
    return 0;
}

// JAVA implementation of above approach
 
import java.util.*;
 
class GFG
{
    public static int findY(int x)
    {
        if (x > 2)
            return x - 2;
     
        return x + 2;
    }
 
    // Driver code
    public static void  main(String [] args)
    {
        int x = 5;
        System.out.println(findY(x));
 
    }
     
}
 
 
// This code is contributed
// by ihritik

# Python3 implementation of above
# approach
 
def findY(x):
 
    if (x > 2):
        return x - 2
     
    return x + 2
 
# Driver code
if __name__=='__main__':
    x = 5
    print(findY(x))
 
# This code is contributed
# by ihritik

// C# implementation of above approach
using System;
 
class GFG
{
public static int findY(int x)
{
    if (x > 2)
        return x - 2;
 
    return x + 2;
}
 
// Driver code
public static void Main()
{
    int x = 5;
    Console.WriteLine(findY(x));
}
}
 
// This code is contributed
// by Subhadeep

<?php
// PHP implementation of above approach
function findY($x)
{
    if ($x > 2)
        return $x - 2;
 
    return $x + 2;
}
 
// Driver code
$x = 5;
echo (findY($x));
 
// This code is contributed
// by Shivi_Aggarwal
?>

<script>
 
// JavaScript implementation of above approach
 
// Function to check whether it is possible
// or not to move from (0, 0) to (x, y)
// in exactly n steps
function findY(x)
{
    if (x > 2)
        return x - 2;
 
    return x + 2;
}
 
// Driver code
 
var x = 5;
document.write(findY(x));
 
// This code is contributed by Ankita saini
 
</script>

Producción:  

3