Here is the snippet,

    Scanner scn = new Scanner(System.in);
    BigInteger t1 = new BigInteger(scn.nextInt()+"");
    BigInteger t2 = new BigInteger(scn.nextInt()+"");
    int n = scn.nextInt();

    BigInteger temp = new BigInteger("0");
    for(int i=3;i<=n;i++){
        temp = t2;
        t2 = t2.multiply(t2);
        t2 = t2.add(t1);
        t1 = temp;
    }
    System.out.println(t2);