题解

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

const int MOD = 10000;

int fff(int n) {
    if (n <= 3) {
        return 1;
    }
    int a = 1, b = 1, c = 1;
    int re;
    for (int i = 4; i <= n; ++i) {
        re = (a + b + c) % MOD;
        a = b;
        b = c;
        c = re;
    }
    return re;
}

int main() {
    int n;
    cin >> n;
    int tmp = fff(n);
    cout << tmp << endl;
    return 0;
}