using System; class test1 { static void Main(string[] args) { int n = int.Parse(Console.ReadLine()); int a = 1; int b = 2; int c = 2; int bp = (n == 1) ? a : b; int r = 1000000007; for (int i = 3; i < n; i++) { bp = (b + a > r) ? (b + a) % r : (b + a); a = b; b = c; c = bp; } Console.WriteLine(bp); } }