import java.util.*;

public class Main {
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int mod = 1000000007;
		int[][] dp = new int[n+1][3];
		dp[0][0] = 1;
		for(int i=1;i<n+1;i++){
			for(int j=0;j<3;j++){
				if(j==0){
					dp[i][1]=dp[i-1][0];
					dp[i][1]%=mod;
				}
				else if(j==1){
					dp[i][2]+=dp[i-1][1];
					dp[i][2]%=mod;
					dp[i][0]+=dp[i-1][1];
					dp[i][0]%=mod;
				}else{
					dp[i][0]+=dp[i-1][2];
					dp[i][0]%=mod;
				}
			}
		}
		int ans = 0;
		for(int i=0;i<3;i++){
			ans+=dp[n][i];
			ans%=1000000007;
		}
		System.out.println(ans);
	}
}