You have an array a with length n, you can perform operations. Each operation is like this: choose two adjacent elements from a, say x and y, and replace one of them with gcd(x, y), where gcd denotes the [greatest common divisor](https://en.wikipedia.org/wiki/Greatest_common_divisor).

What is the minimum number of operations you need to make all of the elements equal to 1?

Input

The first line of the input contains one integer n (1 ≤ n ≤ 2000) — the number of elements in the array.

The second line contains n space separated integers a1, a2, ..., an (1 ≤ ai ≤ 109) — the elements of the array.

Output

Print -1, if it is impossible to turn all numbers to 1. Otherwise, print the minimum number of operations needed to make all numbers equal to 1.

Examples

Input

5
2 2 3 4 6


Output

5


Input

4
2 4 6 8


Output

-1


Input

3
2 6 9


Output

4

Note

In the first sample you can turn all numbers to 1 using the following 5 moves:

  * [2, 2, 3, 4, 6]. 
  * [2, 1, 3, 4, 6]
  * [2, 1, 3, 1, 6]
  * [2, 1, 1, 1, 6]
  * [1, 1, 1, 1, 6]
  * [1, 1, 1, 1, 1]



We can prove that in this case it is not possible to make all numbers one using less than 5 moves.

import java.io.*;
import java.util.*;

public class C892 {
	
	long gcd(long a, long b) {
        while(b > 0) {
            long t = b;
            b = a%b;
            a = t;
        }
        return a;
    }

	private void solve() throws Exception {
		int n = nextInt();
		long[] a = new long[n];
		for(int i = 0; i < n; i++) a[i] = nextLong();
		int min = n+1;
		int count = 0;
		for(int i = 0; i < n; i++){
			if(a[i] == 1) count++;
			long d = a[i];
			for(int j = i; j < n; j++){
				d = gcd(d, a[j]);
				if(d == 1) {
					min = Math.min(min, j-i);
					break;
				}
			} 
		}
		int res = count > 0? n-count : n-1+min;
		out.println(min>n?-1:res);
	}

	public static void main(String[] args) {
		new C892().run();
	}

	private BufferedReader in;
	private PrintWriter out;
	private StringTokenizer tokenizer;

	public void run() {
		try {
			in = new BufferedReader(new InputStreamReader(System.in));
			tokenizer = null;
			out = new PrintWriter(System.out);
			solve();
			in.close();
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	private int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}

	private long nextLong() throws IOException {
		return Long.parseLong(nextToken());
	}

	private float nextFloat() throws IOException {
		return Float.parseFloat(nextToken());
	}

	private String nextLine() throws IOException {
		return new String(in.readLine());
	}

	private String nextToken() throws IOException {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			tokenizer = new StringTokenizer(in.readLine());
		}
		return tokenizer.nextToken();
	}


}

