import math

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

M = 2*10**5+5

count = [0]*M

for a in A:
    count[a] += 1


if count[1]:
    ans = 1
    print(ans)
    for i in range(n-1):
        print(1,2)
    
    exit()

ans = 10**18
if count[0]:
    ans = 0
    print(ans)
    for i in range(n-1):
        print(1,2)

    exit()

target = []
dic = {}
for ind,a in enumerate(A):
    now = a
    for i in range(2,int(a**0.5)+1):
        if now%i:
            continue
        if i in dic:
            target = [a,dic[i]]
        
        while now % i == 0:
            now //= i
        dic[i] = a

    if now != 1:
        dic[now] = a
    
if target:
    first = []
    for i,a in enumerate(A):
        if a in target:
            first.append(i+1)
            target.remove(a)
    
    print(0)
    print(*first)
    for i in range(n-2):
        print(1,2)
    exit()


even = []
odd = []
for i,a in enumerate(A):
    if a%2 == 0:
        even.append(i+1)
    else:
        odd.append(i+1)

assert len(even) < 2

if n == 2:
    ans = (A[0]-1)*(A[1]-1)
    print(ans)
    print(1,2)
    exit()


if even == []:
    if n > 4:
        print(0)
    else:
        ans = (A[0]-1)*(A[1]-1)

        ans = (ans-1)*(A[2]-1)
        print(ans)

    for i in range(n-1):
        print(1,2)


    exit()



else:
    ans = 0
    print(0)
    print(odd.pop(),odd.pop())
    print(n-1,even.pop())
    for i in range(n-3):
        print(1,2)