// https://prologin.org/train/2020/qualification/marche_nocturne
#include <iostream>
//#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
//#include <cstdio>
//#include <cstdlib>
#include <cstdint>
using namespace std;

int main()
{
	uint32_t n = 0;
	cin >> n;

	auto m = vector<uint32_t>(n, 0);
	for(uint32_t i = 0; i < n; i++)
		cin >> m[i];

	//cout << accumulate(m.begin() + 1, m.begin() + 1 + 3, 0) << '\n';

	uint32_t prix = 0;
	cin >> prix;

	auto mini = *min_element(m.begin(), m.end());
	if(mini == prix)
	{
		cout << 1 << '\n';
		return 0;
	}
	for(uint32_t k = 2; k <= n; k++)
	{
		for(uint32_t i = 0; i <= n - k; i++)
		{
			if(accumulate(m.begin() + i, m.begin() + i + k, 0) == prix)
			{
				cout << k << '\n';
				return 0;
			}
		}
	}
	cout << -1 << '\n';

	return 0;
} // main()