import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		String[] sa = br.readLine().split(" ");
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = Integer.parseInt(sa[i]);
		}
		br.close();

		if (n >= 4) {
			PrintWriter pw = new PrintWriter(System.out);
			pw.println(0);
			for (int i = 0; i < n - 1; i++) {
				pw.println("1 2");
			}
			pw.flush();

		} else if (n == 2) {
			Map<Long, Integer> map0 = bunkai(a[0]);
			Map<Long, Integer> map1 = bunkai(a[1]);
			long m = (a[0] - 1) * (a[1] - 1);
			for (Long k : map0.keySet()) {
				if (map1.containsKey(k)) {
					m = 0;
					break;
				}
			}
			System.out.println(m);
			System.out.println("1 2");

		} else {
			Map<Long, Integer> map0 = bunkai(a[0]);
			Map<Long, Integer> map1 = bunkai(a[1]);
			Map<Long, Integer> map2 = bunkai(a[2]);
			Map<Long, Integer> map01 = bunkai((a[0] - 1L) * (a[1] - 1));
			Map<Long, Integer> map12 = bunkai((a[1] - 1L) * (a[2] - 1));
			Map<Long, Integer> map20 = bunkai((a[2] - 1L) * (a[0] - 1));
			for (Long k : map0.keySet()) {
				if (map12.containsKey(k)) {
					System.out.println(0);
					System.out.println("2 3");
					System.out.println("1 2");
					return;
				}
			}
			for (Long k : map1.keySet()) {
				if (map20.containsKey(k)) {
					System.out.println(0);
					System.out.println("1 3");
					System.out.println("1 2");
					return;
				}
			}
			for (Long k : map2.keySet()) {
				if (map01.containsKey(k)) {
					System.out.println(0);
					System.out.println("1 2");
					System.out.println("1 2");
					return;
				}
			}

			System.out.println(((a[0] - 1L) * (a[1] - 1) - 1) * (a[2] - 1));
			System.out.println("1 2");
			System.out.println("1 2");
		}
	}

	static Map<Long, Integer> bunkai(long n) {
		Map<Long, Integer> soinsu = new HashMap<>();
		int end = (int) Math.sqrt(n);
		long d = 2;
		while (n > 1) {
			if (n % d == 0) {
				n /= d;
				soinsu.put(d, soinsu.getOrDefault(d, 0) + 1);
				end = (int) Math.sqrt(n);
			} else {
				if (d > end) {
					d = n - 1;
				}
				d++;
			}
		}
		return soinsu;
	}
}