#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll mod = 1000000007;
int main() {
    ios::sync_with_stdio(false);
    ll n; cin >> n;
    ll dp[n+1];
    dp[0] = 1;
    dp[1] = 1;
    dp[2] = 2;

    for (int i = 3; i <= n; i++) {
        dp[i] = (dp[i-2]%mod + dp[i-3]%mod)%mod;
    }
    cout << dp[n] << endl;





    return 0;
}