#include <stdio.h>

#define ANS (1000000000+7)

int searchDP(int n);

int main(void)
{
	int n,ret;
	scanf("%d",&n);

	ret = searchDP(n);

	printf("%d\n",ret);
	
	return 0;
}

int searchDP(int n)
{
	int i,j;
	long long dp[4];
	if      (n==1) return 1;
	else if (n==2) return 2;
	else if (n==3) return 2;

	dp[0] = 1;
	dp[1] = 2;
	dp[2] = 2;
	for (i=3;i<n;i++) {
		dp[3] = dp[0] + dp[1];
		for (j=1;j<4;j++) {
			dp[j-1] = dp[j];
		}
	}
	return (int)(dp[3]%ANS);
}