#include<bits/stdc++.h>
#define REP(x,y,z) for(int x=y;x<=z;x++)
#define FORD(x,y,z) for(int x=y;x>=z;x--)
#define MSET(x,y) memset(x,y,sizeof(x))
#define FOR(x,y) for(__typeof(y.begin()) x=y.begin();x!=y.end();x++)
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define SZ size()
#define M 1000005
#define MOD 1000000007
void RI(){}
template<typename... T>
void RI( int& head, T&... tail ) {
    scanf("%d",&head);
    RI(tail...);
}
using namespace std;
typedef long long LL;
int n;
LL dp[M][3];
int main()
{
	while(~scanf("%d",&n))
	{
		MSET(dp,0);
		dp[0][0]=1;
		REP(i,1,n)REP(j,0,2)
		{
			if(j==0) dp[i][j] = dp[i-1][1]+dp[i-1][2];
			else dp[i][j] = dp[i-1][j-1];
			dp[i][j] %= MOD;
		}

		printf("%lld\n", (dp[n][0]+dp[n][1]+dp[n][2])%MOD);
	}
	return 0;
}