C++(씨쁠쁠)(cplusplus)-백준(baekjoon)(BaekJoon)코딩 1964번:오각형, 오각형, 오각형… 답

#include <iostream>
using namespace std;
int main()
{
    long long n;
    cin >> n;
    cout << (3 * (n*n + n) / 2 + n + 1) % 45678 << endl;
}