// yukicoder: No.533 Mysterious Stairs
// 2019.7.26 bal4u
// For n>6, a(n) = a(n-3) + a(n-4) + a(n-5) + 2*a(n-6). (End) 

#include <stdio.h>

#define MOD 1000000007
unsigned a[1000005] = {1,1,1,3,3,4,8,9,12,21,27};

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

	scanf("%d", &N);
	if (N <= 10) k = a[N];
	else {
		for (i = 11; i <= N; i++) 
			a[i] = ((long long)a[i-3] + a[i-4] + a[i-5] + (a[i-6]<<1)) % MOD;
		k = a[N];
	}
	printf("%u\n", k);
	return 0;
}