#include <stdio.h>

#define MOD 1000000007

int main(void) {
	int n, i, dp[3] = {0, 1, 0};
	scanf("%d", &n);
	for(i = 1; i < n; i++) {
		int temp[3] = { dp[0], dp[1], dp[2] };
		dp[0] = ( temp[1] + temp[2] ) % MOD;
		dp[1] = temp[0];
		dp[2] = temp[1];
	}
	
	printf("%d\n", ( dp[0] + dp[1] + dp[2] ) % MOD );
	
	return 0;
}