# random

import sys, random
from math import gcd
from itertools import permutations
from collections import deque
input = sys.stdin.readline

def f(x, y):
    if(gcd(x, y) == 1):
        return (x - 1) * (y - 1)
    return 0


n = int(input())
a = list(map(int, input().split()))

ans = 10 ** 18
ops = []
if(n == 2):
    ans = f(a[0], a[1])
    ops = [(a[0], a[1])]
elif(n == 3):
    for p in permutations(a):
        x = f(p[0], p[1]);  y = f(x, p[2])
        if(ans >= y):
            ans = y
            ops = [(p[0], p[1]), (x, p[2])]
        x = f(p[1], p[2]);  y = f(x, p[0])
        if(ans >= y):
            ans = y
            ops = [(p[1], p[2]), (x, p[0])]
else:
    que = deque(a)
    for i in range(n - 1):
        if(i % 50000 == 0):
            random.shuffle(que)
        x, y = que.popleft(), que.popleft()
        que.append(f(x, y))
        ops.append((x, y))
    ans = que.popleft()

print(ans)
for x, y in ops:
    print(x, y)