UVa 11934 - Magic Formula

#include <iostream>
using namespace std;

#define ll long long

int main() {
	while (true) {
		ll a, b, c, d, L;
		cin >> a >> b >> c >> d >> L;
		if (a == 0 && b == 0 && c == 0 && d == 0 && L == 0)
			break;
		ll divisible_fx_count = 0;
		for (ll x = 0; x <= L; x++) {
			if ((a * x * x + b * x + c) % d == 0)
				divisible_fx_count++;
		}
		cout << divisible_fx_count << endl;
	}
	return 0;
}