Problem:
Score : 600 points

Problem Statement

Snuke has an integer sequence, a, of length N. The i-th element of a (1-indexed) is a_{i}.

He can perform the following operation any number of times:

Operation: Choose integers x and y between 1 and N (inclusive), and add a_x to a_y.

He would like to perform this operation between 0 and 2N times (inclusive) so that a satisfies the condition below. Show one such sequence of operations.
It can be proved that such a sequence of operations always exists under the constraints in this problem.

Condition: a_1 \leq a_2 \leq ... \leq a_{N}

Constraints

2 \leq N \leq 50

-10^{6} \leq a_i \leq 10^{6}

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_{N}

Output

Let m be the number of operations in your solution. In the first line, print m.
In the i-th of the subsequent m lines, print the numbers x and y chosen in the i-th operation, with a space in between.
The output will be considered correct if m is between 0 and 2N (inclusive) and a satisfies the condition after the m operations.

Sample Input 1

3
-2 5 -1

Sample Output 1

2
2 3
3 3

After the first operation, a = (-2,5,4).

After the second operation, a = (-2,5,8), and the condition is now satisfied.

Sample Input 2

2
-1 -3

Sample Output 2

1
2 1

After the first operation, a = (-4,-3) and the condition is now satisfied.

Sample Input 3

5
0 0 0 0 0

Sample Output 3

0

The condition is satisfied already in the beginning.

Solution in Python (3.8.2) (judge verdict: Runtime Error)

N = int(input())
A = [int(i) for i in input().split()]

S = min(A)
L = max(A)

c = 0
B = []

if S == L:
    pass

elif S >= 0 and L > 0:
    for i in range(N-1):
        if A[i+1] >= A[i]:
            pass
        else:
            A[i+1] += A[i]
            c += 1
            B.append((i+1, i+2))

elif L <= 0 and S < 0:
    for i in range(N-1):
        if A[-i-2] <= A[-i-1]:
            pass
        else:
            A[-i-2] += A[-i-1]
            c += 1
            B.append((N-i, N-i-1))

else:
    if L >= -S:
        l = A.index(L)
        if A[0] < 0:
            A[0] += L
            c += 1
            B.append((l+1, 1))
        for i in range(N-1):
            if A[i+1] >= A[i]:
                pass
            else:
                if A[i+1] < 0:
                    A[i+1] += L
                    c += 1
                    B.append((l+1, i+2))
                A[i+1] += A[i]
                c += 1
                B.append((i+1, i+2))
                if i+1 == l:
                    L = A[l]
    else:
        s = A.index(S)
        if A[-1] > 0:
            A[-1] += S
            c += 1
            B.append((s+1, N))
        for i in range(N-1):
            if A[-i-2] <= A[-i-1]:
                pass
            else:
                if A[-i-2] > 0:
                    A[-i-2] += S
                    c += 1
                    B.append(s+1, N-i-1)
                A[-i-2] += A[-i-1]
                c += 1
                B.append((N-i, N-i-1))
                if -i-2 == s:
                    S = A[s]

if c == 0:
    print(c)
else:
    print(c)
    for i in range(c):
        print(B[i][0], B[i][1])