// yukicoder: No.533 Mysterious Stairs
// 2019.7.26 bal4u

#include <stdio.h>

#define MOD 1000000007
unsigned dp[1000005][4];

int main()
{
	int i, j, k, N;
	unsigned ans;

	scanf("%d", &N);
	dp[0][1] = 1, dp[1][1] = 1, dp[2][2] = 1;
	dp[3][1] = dp[3][2] = dp[3][3] = 1;
	for (i = 4; i <= N; i++) {
		for (j = 1; j <= 3; j++) for (k = 1; k <= 3; k++) if (k != j) {
			dp[i][j] += dp[i-j][k];
		}
		for (j = 1; j <= 3; j++) dp[i][j] %= MOD;
	}
	ans = 0; for (j = 1; j <= 3; j++) ans += dp[N][j];
	printf("%d\n", (int)(ans % MOD));
	return 0;
}