There are only two ways to tell somebody thanks: Kudos and Marked Solutions Unofficial Forum Rules and Guidelines "Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5
first loop: input+input => 2input second loop: 2input+input=>3input thirdt loop: 3input+input=>4input so answer is D (or do I misunderstood the question?)