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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<long long> A(N);
    for(auto &a : A) cin >> a;
    if(N == 2){
        bool zero = false;
        if(gcd(A.at(0),A.at(1)) != 1 || A.at(0) == 0 || A.at(1) == 0) cout << 0 << endl;
        else cout << (A.at(0)-1)*(A.at(1)-1) << endl;
        cout << "1 2" << endl;
    }
    else if(N == 3){
        if(A.at(0)%2 == 0 || A.at(1)%2 == 0 || A.at(2)%2 == 0 || *min_element(A.begin(),A.end()) == 1){
            cout << 0 << endl << "1 2" << endl << "1 2" << endl;
        }
        else{
            long long ans = 1,left = max_element(A.begin(),A.end())-A.begin();
            for(int i=0; i<3; i++){
                if(i == left) continue;
                ans *= A.at(i)-1;
            }
            ans = (ans-1)*(A.at(left)-1);
            cout << ans << endl;
            bool output = false;
            for(int i=0; i<3; i++){
                if(left == i) continue;
                if(output) cout << " ";
                output = true;
                cout << i+1;
            }  
            cout << endl << "1 2" << endl;
        }
    }
    else{
        cout << 0 << endl;
        vector<int> odd,even;
        for(int i=0; i<N; i++){
            if(A.at(i)%2) odd.push_back(i+1);
            else even.push_back(i+1); 
        }
        if(even.size() >= 2){
            cout << even.at(0) << " " << even.at(1) << endl;
            N -= 1;
        }
        else{
            cout << "1 2" << endl << "1 2" << endl;
            N -= 2;
        }

        while(N != 1){
            cout << "1 " << N << endl;
            N--; 
        }
    }
}