#include<bits/stdc++.h>
#define ALL(v) std::begin(v),std::end(v)
using lint=long long;
using lubl=long double;
lint mod=1'000'000'007;
struct mint{
    lint value;
    mint()=default;
    mint(lint x):value(x){}
};
std::ostream&operator<<(std::ostream&os,mint x){return os<<x.value;}
mint operator+(mint x,mint y){lint z=x.value+y.value;if(mod<=z)z-=mod;return mint{z};}
mint&operator+=(mint&x,mint y){return x=x+y;}
int main(){
    std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);
    std::cout.setf(std::ios_base::fixed);std::cout.precision(15);
    lint n;std::cin>>n;
    std::vector<std::vector<mint>>dp(n+1,std::vector<mint>(4));
    for(lint i=1;i<=std::min(3ll,n);i++)dp.at(i).at(i)=1;
    for(lint i=1;i<n;i++){
        for(lint j=1;j<=3;j++){
        for(lint k=1;k<=3&&i+k<=n;k++){
            if(j==k)continue;
            dp.at(i+k).at(k)+=dp.at(i).at(j);
        }}
    }
    std::cout<<std::accumulate(ALL(dp.at(n)),mint{0})<<'\n';
}