#include <bits/stdc++.h>

#define pb push_back
#define all(v) v.begin(), v.end()
#define sz(v) int(v.size())

using namespace std;

class EllysRain
{
public:

	std::vector<int> v;

	int get_next(int P_prev, int M, int A, int L){
		return (P_prev * M + A) % (L + 1);
	}

	bool check(int K, int D, int L){
		std::vector<int> wow(v.begin(), v.begin()+K);
		sort(all(wow));

		if(wow.front() > D or wow.back() < L-D)
			return 0;

		for (int i = 0; i+1 < sz(wow); ++i)
		{
			if(wow[i+1]-wow[i] > D)
				return 0;
		}

		return 1;
	}

	int getTime(int L, int D, int N, int P1, int M, int A){
		for (int i = 1; i <= N; ++i)
		{
			v.pb(P1);
			P1 = get_next(P1, M, A, L);
		}

		int low = 1, high = N, best = -1;

		while(low <= high){
			int mid = (low + high) >> 1;
			if(check(mid, D, L)){
				high = mid-1;
				best = mid;
			}
			else{
				low = mid + 1;
			}
		}
		return best;
	}
	
};

int main(){
	int l, d, n, p1, m, a;
	cin >> l >> d >> n >> p1 >> m >> a;
	EllysRain x;
	cout<< x.getTime(l, d, n, p1, m, a);
	return 0;
}