Custom Fibonacci-Like Sequence

You are given three integers n, a, and b. Your task is to compute the n-th term of a Fibonacci-like sequence defined as follows:

$$F(1)=a, \quad F(2)=b, \quad F(n)=F(n-1)+F(n-2) \quad \text{for } n>2.$$

For example, given n = 5, a = 4, and b = 7, the sequence is: 4, 7, 11, 18, 29, so the output should be 29.

inputFormat

The input consists of a single line containing three space-separated integers: n, a, and b, where n denotes the term to compute, and a and b are the first two terms of the sequence respectively.

outputFormat

Output a single integer which is the n-th term of the Fibonacci-like sequence.

1 4 7

4