E - Three ones

#include <bits/stdc++.h>
using namespace std;

#define int long long

int n;


signed main()
{
    cin >> n;
    int f[n + 1];
    f[0] = 1;
    f[1] = 2;
    f[2] = 4;
    for(int i = 3; i <= n; i++){
        f[i] = f[i - 1] + f[i - 2] + f[i - 3];
        f[i] %= 12345;
    }
    cout << f[n] << endl;
}