from math import gcd


def f(a, b):
    if gcd(a, b) == 1:
        return a * b - a - b + 1
    else:
        return 0


n = int(input())
A = list(map(int, input().split()))
odd = []
even = []
for i, a in enumerate(A):
    if a % 2 == 1:
        odd.append(i)
    else:
        even.append(i)

if len(even) >= 2:
    i, j = even[:2]
    print(0)
    print(i + 1, j + 1)
    for i in range(n - 2, 0, -1):
        print(i, i + 1)
elif len(even) >= 1 and len(odd) >= 2:
    i, j = odd[:2]
    print(0)
    print(i + 1, j + 1)
    ii = even[0]
    if j < ii:
        ii -= 1
    if i < ii:
        ii -= 1
    print(ii + 1, n - 1)
    for i in range(n - 3, 0, -1):
        print(i, i + 1)
elif len(odd) >= 4:
    i, j, k, l = odd[:4]
    print(0)
    print(k + 1, l + 1)
    print(i + 1, j + 1)
    print(n - 3, n - 2)
    for i in range(n - 4, 0, -1):
        print(i, i + 1)
elif n == 2:
    a, b = A
    print(f(a, b))
    print(1, 2)
else:
    assert n == 3
    a, b, c = A
    mi1 = f(f(a, b), c)
    mi2 = f(f(a, c), b)
    mi3 = f(f(b, c), a)
    mi = min(mi1, mi2, mi3)
    print(mi1)
    if mi == mi1:
        print(1, 2)
    elif mi == mi2:
        print(1, 3)
    else:
        print(2, 3)
    print(1, 2)