import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    long MOD = (long)Math.pow(10, 9) + 7;
    long[] dp1 = new long[N + 1];
    long[] dp2 = new long[N + 1];
    long[] dp3 = new long[N + 1];
    dp1[1] = 1;
    if(N > 1) dp2[2] = 1;
    if(N > 2) {
      dp1[3] = 1;
      dp2[3] = 1;
      dp3[3] = 1;
    }
    for(int i = 4; i < N + 1; i++) {
      dp1[i] = (dp2[i - 1] + dp3[i - 1]) % MOD;
      dp2[i] = (dp1[i - 2] + dp3[i - 2]) % MOD;
      dp3[i] = (dp1[i - 3] + dp2[i - 3]) % MOD;
    }
    long ans = dp1[N];
    ans = (ans + dp2[N]) % MOD;
    ans = (ans + dp3[N]) % MOD;
    System.out.println(ans);
  }
}