#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef long long int ll;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define iterate(b,e) for(auto cnt=(b);cnt!=(e);++cnt)
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795
template<typename T1, typename T2>
ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }



ll solve_MLE(int n) {
    vector<array<ll, 4>> dp(n + 4);

    dp[1][1] = 1; // 1jump で 1step 登る．次は 1jump は使えない．
    dp[2][2] = 1; // 2jump で 2step 登る．次は 2jump は使えない．
    dp[3][3] = 1; // 3jump で 3step 登る．次は 3jump は使えない．

    for (int i = 1; i < n; ++i) {
        // 1jumpする．
        dp[i + 1][1] = (dp[i + 1][1] + (dp[i][2] + dp[i][3])) % MD;
        // 2jumpする．
        dp[i + 2][2] = (dp[i + 2][2] + (dp[i][1] + dp[i][3])) % MD;
        // 3jumpする．
        dp[i + 3][3] = (dp[i + 3][3] + (dp[i][1] + dp[i][2])) % MD;
    }
    return (dp[n][1] + dp[n][2] + dp[n][3]) % MD;
}

int main() {
    int n;
    cin >> n;
    cout << solve_MLE(n) << endl;
}