#include<bits/stdc++.h>
using namespace std;
using ll=long long;

pair<int,vector<array<int,2>>>dfs(vector<ll> v){
  assert(!v.empty());
  if(v.size()==1){
    return make_pair(v[0],vector<array<int,2>>());
  }
  int N=v.size();
  vector<array<int,2>>ret;
  ll m=1e18;
  for(int i=0;i<N;i++){
    for(int j=i+1;j<N;j++){
      vector v2(0,0ll);
      for(int k=0;k<N;k++){
        if(k!=i&&k!=j)v2.push_back(v[k]);
      }
      if(gcd(v[i],v[j])!=1)v2.push_back(0);
      else v2.push_back(v[i]*v[j]-v[i]-v[j]+1);
      auto [n,rv]=dfs(v2);
      if(n<m){
        m=n;
        rv.push_back({i+1,j+1});
        ret=rv;
      }
    }
  }
  return make_pair(m,ret);
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int N;
  cin>>N;
  vector A(N,0ll);
  int idx1=-1;
  for(int i=0;i<N;i++){
    cin>>A[i];
    if(A[i]==1){
      idx1=i;
    }
  }
  if(idx1==-1){
    if(N<4){
      auto [m,v]=dfs(A);
      cout<<m<<'\n';
      for(auto i:v)cout<<i[0]<<' '<<i[1];
    }else{
      cout<<"0\n";
      vector odd(0,0),even(0,0);
      for(int i=0;i<N;i++){
        if(A[i]%2){
          odd.push_back(i);
        }else{
          even.push_back(i);
        }
      }
      while(even.size()<2){
        int k1=odd.back();
        odd.pop_back();
        int k2=odd.back();
        odd.pop_back();
        for(int &i:even){
          if(i>k1)i-=1;
        }
        for(int &i:even){
          if(i>k2)i-=1;
        }
        even.push_back(odd.size()+even.size());
        cout<<k1+1<<' '<<k2+1<<'\n';
      }
      cout<<even[0]+1<<' '<<even[1]+1<<'\n';
      for(int i=odd.size()+even.size()-1;i>1;i--){
        cout<<i<<" 1\n";
      }
    }
  }else{
    cout<<"0\n";
    if(idx1==0){
      cout<<"1 2\n";
    }else{
      cout<<idx1+1<<" 1\n";
    }
    for(int i=N-1;i>1;i--){
      cout<<i<<" 1\n";
    }
  }
}