#include <iostream>
using namespace std;
#define NUM 1000000007
int main(){
    int n;
    cin>>n;
    int temp[n+1];
    temp[0]=0;temp[1]=1;temp[2]=2;
    for(int i=3;i<=n;i++)
        temp[i] = (temp[i-1]%NUM+temp[i-2]%NUM)%NUM;
    cout<<temp[n]<<endl;
    return 0;
}