#include<stdio.h>
#define mod 1000000007

int main(){
	int n; scanf("%d",&n);
	int k1=1,k2=0,p=0,i;
	for(i=1;i<n;++i){
		int tp=p;
		p=((long)k1+k2)%mod,k2=k1,k1=tp;
	}
	printf("%ld\n",((long)k1+k2+p)%mod);
}