Insect Population Growth

You are given the initial populations of a species of insects for the first two months, denoted as P0 and P1. For each subsequent month n (with n ≥ 3), the population is the sum of the populations from the two previous months. Formally, the recurrence relation is given by:

\( P(n) = P(n-2) + P(n-1) \) for \( n \geq 3 \)

Your task is to compute the insect population at month N.

inputFormat

The input consists of a single line containing three space-separated integers:

• N: the number of months
• P0: the population at month 1
• P1: the population at month 2

Constraints: N will be at least 1. For N = 1 or N = 2, the answer is P0 or P1 respectively.

outputFormat

Output a single integer representing the insect population at month N.

5 3 5

21