# 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;
        }
    }
    vector<pair<int, int>> ans(n - 1);
    rep(i, n - 1){
        ll minl = hinf<ll>();
        ll mini = -1;
        rep(j, len(a)){
            if(chmin(minl, a[j]))mini = j;
        }
        ll minl2 = hinf<ll>();
        ll mini2 = -1;
        rep(j, len(a)){
            if(j == mini)continue;
            if(chmin(minl2, a[j]))mini2 = j;
        }
        ans[i] = {mini, mini2};
        vector<ll> a2;
        rep(j, len(a)){
            if(j == mini)continue;
            if(j == mini2)continue;
            a2.push_back(a[j]);
        }
        a2.push_back((minl - 1) * (minl2 - 1));
        a = a2;
    }
    cout << a[0] << endl;
    rep(i, n - 1){
        cout << ans[i].first + 1 << " " << ans[i].second + 1 << endl;
    }
}

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