# include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
const double pi = acos(-1);
template<class T>constexpr T inf() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T hinf() { return inf<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); }
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); }
template<class T> bool chmin(T& a,T b) { if(a > b){a = b; return true;} return false; }
template<class T> bool chmax(T& a,T b) { if(a < b){a = b; return true;} return false; }
template<class T> bool is_sqare(T a) { if(floor(sqrt(a)) * floor(sqrt(a)) == a){ return true; }return false; }
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(ll n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(ll n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
ll gcd(ll a, ll b) { if (b == 0)return a; return gcd(b, a%b); };
ll lcm(ll a, ll b) { ll g = gcd(a, b); return a / g*b; };
template<class T> using dijk = priority_queue<T, vector<T>, greater<T>>;
# define all(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        sort(all((wpwpw)));(wpwpw).erase(unique(all((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(all((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(all((rprpr)),(rprpr).begin(),TU<char>)
# define rep(i,upupu)         for(ll i = 0, i##_len = (upupu);(i) < (i##_len);(i)++)
# define reps(i,opopo)        for(ll i = 1, i##_len = (opopo);(i) <= (i##_len);(i)++)
# define len(x)                ((int)(x).size())
# define bit(n)               (1LL << (n))
# define pb push_back
#ifdef LOCAL
#  include "_debug_print.hpp"
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

struct INIT{
    INIT(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(0);
        cout << fixed << setprecision(20);
    }
}INIT;

void solve(){
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i, n)cin >> a[i];
    
    vector<vector<int>> div(200000 + 1);
    rep(i, n){
        int sq = sqrt(a[i]);
        reps(j, sq){
            if(a[i] % j)continue;
            div[j].push_back(i);
            if(a[i] / j != j)div[a[i] / j].push_back(i);
        }
    }

    reps(i, 200000){
        if(i == 1)continue;
        if(len(div[i]) >= 2){
            cout << 0 << endl;
            int l = div[i][0], r = div[i][1];
            cout << l + 1 << " " << r + 1 << endl;
            rep(j, n - 2){
                cout << "1 " << n - 1 - j << endl;
            }
            return;
        }
    }
    ll minl_ = hinf<ll>();
    rep(i, n)chmin(minl_, a[i]);

    if(minl_ == 2){
        if(n >= 3){
            cout << 0 << endl;
            int idx = -1;
            rep(i, n)if(a[i] == 2)idx = i;
            int l = (idx + 1) % n, r = (idx + 2) % n;
            cout << l + 1 << " " << r + 1 << endl;
            vector<ll> a2;
            rep(i, n){
                if(i == l)continue;
                if(i == r)continue;
                a2.push_back(a[i]);
            }
            int idx2 = 0;
            while(a2[idx2] != 2)idx2++;
            cout << idx2 + 1 << " " << n - 1 << endl;
            rep(j, n - 3){
                cout << "1 " << n - 2 - j << endl;
            }
            return;
        }
    }else{
        if(n >= 4){
            cout << 0 << endl;
            cout << "1 2" << endl;
            cout << "1 2" << endl;
            vector<ll> a2;
            for(int i = 4;i < n;i++){
                a2.push_back(a[i]);
            }
            a2.push_back((a[0] - 1) * (a[1] - 1));
            a2.push_back((a[2] - 1) * (a[3] - 1));
            sort(all(a2));
            int l = -1, r = -1;
            rep(i, len(a2)){
                if(l == -1 && a2[i] % 2 == 0)l = i;
                else if(a2[i] % 2 == 0)r = i;
            }
            cout << l + 1 << " " << r + 1 << endl;
            rep(j, n - 4){
                cout << "1 " << n - 3 - j << endl;
            }
            return;
        }
    }
    if(n == 2){
        cout << (a[0] - 1) * (a[1] - 1) << endl;
        cout << "1 2" << endl;
        return;
    }
    // n == 3
    ll x = ((a[0] - 1) * (a[1] - 1) - 1) * (a[2] - 1);
    ll y = ((a[0] - 1) * (a[2] - 1) - 1) * (a[1] - 1);
    ll z = ((a[1] - 1) * (a[2] - 1) - 1) * (a[0] - 1);
    ll minl = min({x, y ,z});
    cout << minl << endl;
    if(minl == x){
        cout << "1 2" << endl;
    }else if(minl == y){
        cout << "1 3" << endl;
    }else{
        cout << "2 3" << endl;
    }
    cout << "1 2" << endl;
}

int main(){
    int t = 1;
    //cin >> t;
    while(t--)solve();
}