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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<vector>
#include<algorithm>
#include<iomanip>
#include<utility>
#include<set>
typedef long long int ll;
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define REP(i,n) for (int i=0;i<signed(n);i++)
#define EREP(i,n) for (int i=1;i<=(n);i++)
#define ALL(a) (a).begin(),(a).end()
//#define EVEL 1

#ifdef EVEL
#define DEB(X) cout << #X << ":" <<X<<" " ;
#define TF(f) f ? cout<<"true  " : cout<<"false ";
#define END cout<<"\n";
#else
#define DEB(X) {}
#define TF(f) {}
#define END {}
#endif
const int MOD = 1000000007;
const ll INF = 20000000000;
struct edge {int to,cost;};
#define VMAX 51
typedef std::pair<int,int> P;

    ll N;
    ll A[52],S[52];
    P B[52];
    ll X,Y;
    ll ans;
int main(){
    ios_base::sync_with_stdio(false);
    cin>>N;
    REP(i,N){
      cin>>A[i];
      B[i].first=A[i];
      B[i].second=i;
    }
    sort(B,B+N);
    X=B[0].first,Y=B[N-1].first;
    cout<<N*2-1<<endl;
    REP(i,N){

        if(abs(Y)-abs(X)>=0){
            cout<<B[N-1].second+1;
        }else{
            cout<<B[0].second+1;
        }
        cout<<" "<<i+1;
        cout<<endl;
    }
    if(abs(Y)-abs(X)>=0){
        REP(i,N-1)cout<<i+1<<" "<<i+2<<endl;
    }else{
        REP(i,N-1)cout<<N-i<<" "<<N-i-1<<endl;
    }

//    cout<<ans<<endl;
    return 0;
}