import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long MOD = (long)Math.pow(10, 9) + 7;
    int N = sc.nextInt();
    // dp[i]は長さ(i+1)のコース数 mod MOD
    long[] dp = new long[N];
    dp[0] = 1;
    if(1 < N) dp[1] = 2;
    if(2 < N) dp[2] = 2;
    for(int i = 3; i < N; i++) {
      dp[i] = (dp[i - 2] + dp[i - 3]) % MOD;
    }
    System.out.println(dp[N - 1]);
  }
}