Problems
Fibonacci sum
Fibonacci sum
Let f(n) be the n-th Fibonacci number, given by
f(1) = 0,
f(2) = 1,
f(n) = f(n-2) + f(n-1), n > 2
Given the value of n, find f(1) + f(2) + ... + f(n).
Input data
One positive integer n (n ≤ 1000).
Output data
Print the value of sum modulo 10^9 + 7.
Examples
Input example #1
5
Output example #1
7