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

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

const int N = 1 << 14;

int d[2][3 * N];


int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	fill(d[0], d[0] + 3 * N, -1);
	fill(d[1], d[1] + 3 * N, -1);
	
	
	int n;
	cin >> n;
	VI a(n);
	FOR(i, 0, n)
		cin >> a[i];
	
	
	d[0][0 + N] = 0;
	queue<PII> q;	
	q.push(MP(0, 0));


	while(SZ(q))
	{
		int t = q.front().F;
		int x = q.front().S;
		q.pop();
		
		FOR(i, 0, n)
		{
			int y = a[i] - x;
			if(0 <= y + N && y + N < 3 * N && d[t ^ 1][y + N] == -1)
			{
				d[t ^ 1][y + N] = d[t][x + N] + 1;
				q.push(MP(t ^ 1, y));
			}
		}
	}
	
	int t;
	cin >> t;
	while(t--)
	{
		int x, y;
		cin >> x >> y;
		
		int ans = -1;
		if((y + x) % 2 == 0)
		{
			int val = (y + x) / 2 + N;
			if(0 <= val && val < 3 * N && d[1][val] != -1)
			{
				ans = d[1][val];
			}
		}
		if((y - x) % 2 == 0)
		{
			int val = (y - x) / 2 + N;
			if(0 <= val && val < 3 * N && d[0][val] != -1)
			{
				if(ans == -1)
					ans = d[0][val];
				else
					ans = min(ans, d[0][val]);
			}
		}
		cout << ans << "\n";
	}
	
	return 0;
}