// #define _GLIBCXX_DEBUG
#pragma GCC optimize("O2,no-stack-protector,unroll-loops,fast-math")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < int(n); i++)
#define per(i, n) for (int i = (n)-1; 0 <= i; i--)
#define rep2(i, l, r) for (int i = (l); i < int(r); i++)
#define per2(i, l, r) for (int i = (r)-1; int(l) <= i; i--)
#define each(e, v) for (auto& e : v)
#define MM << " " <<
#define pb push_back
#define eb emplace_back
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sz(x) (int)x.size()
template <typename T> void print(const vector<T>& v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' ');
    if (v.empty()) cout << '\n';
}
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T> bool chmax(T& x, const T& y) {
    return (x < y) ? (x = y, true) : false;
}
template <typename T> bool chmin(T& x, const T& y) {
    return (x > y) ? (x = y, true) : false;
}
template <class T>
using minheap = std::priority_queue<T, std::vector<T>, std::greater<T>>;
template <class T> using maxheap = std::priority_queue<T>;
template <typename T> int lb(const vector<T>& v, T x) {
    return lower_bound(begin(v), end(v), x) - begin(v);
}
template <typename T> int ub(const vector<T>& v, T x) {
    return upper_bound(begin(v), end(v), x) - begin(v);
}
template <typename T> void rearrange(vector<T>& v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

// __int128_t gcd(__int128_t a, __int128_t b) {
//     if (a == 0)
//         return b;
//     if (b == 0)
//         return a;
//     __int128_t cnt = a % b;
//     while (cnt != 0) {
//         a = b;
//         b = cnt;
//         cnt = a % b;
//     }
//     return b;
// }

struct Union_Find_Tree {
    vector<int> data;
    const int n;
    int cnt;
 
    Union_Find_Tree(int n) : data(n, -1), n(n), cnt(n) {}
 
    int root(int x) {
        if (data[x] < 0) return x;
        return data[x] = root(data[x]);
    }
 
    int operator[](int i) { return root(i); }
 
    bool unite(int x, int y) {
        x = root(x), y = root(y);
        if (x == y) return false;
        if (data[x] > data[y]) swap(x, y);
        data[x] += data[y], data[y] = x;
        cnt--;
        return true;
    }
 
    int size(int x) { return -data[root(x)]; }
 
    int count() { return cnt; };
 
    bool same(int x, int y) { return root(x) == root(y); }
 
    void clear() {
        cnt = n;
        fill(begin(data), end(data), -1);
    }
};

template <int mod> struct Mod_Int {
    int x;

    Mod_Int() : x(0) {}

    Mod_Int(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    static int get_mod() { return mod; }

    Mod_Int& operator+=(const Mod_Int& p) {
        if ((x += p.x) >= mod) x -= mod;
        return *this;
    }

    Mod_Int& operator-=(const Mod_Int& p) {
        if ((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }

    Mod_Int& operator*=(const Mod_Int& p) {
        x = (int)(1LL * x * p.x % mod);
        return *this;
    }

    Mod_Int& operator/=(const Mod_Int& p) {
        *this *= p.inverse();
        return *this;
    }

    Mod_Int& operator++() { return *this += Mod_Int(1); }

    Mod_Int operator++(int) {
        Mod_Int tmp = *this;
        ++*this;
        return tmp;
    }

    Mod_Int& operator--() { return *this -= Mod_Int(1); }

    Mod_Int operator--(int) {
        Mod_Int tmp = *this;
        --*this;
        return tmp;
    }

    Mod_Int operator-() const { return Mod_Int(-x); }

    Mod_Int operator+(const Mod_Int& p) const { return Mod_Int(*this) += p; }

    Mod_Int operator-(const Mod_Int& p) const { return Mod_Int(*this) -= p; }

    Mod_Int operator*(const Mod_Int& p) const { return Mod_Int(*this) *= p; }

    Mod_Int operator/(const Mod_Int& p) const { return Mod_Int(*this) /= p; }

    bool operator==(const Mod_Int& p) const { return x == p.x; }

    bool operator!=(const Mod_Int& p) const { return x != p.x; }

    Mod_Int inverse() const {
        assert(*this != Mod_Int(0));
        return pow(mod - 2);
    }

    Mod_Int pow(long long k) const {
        Mod_Int now = *this, ret = 1;
        for (; k > 0; k >>= 1, now *= now) {
            if (k & 1) ret *= now;
        }
        return ret;
    }

    friend ostream& operator<<(ostream& os, const Mod_Int& p) {
        return os << p.x;
    }

    friend istream& operator>>(istream& is, Mod_Int& p) {
        long long a;
        is >> a;
        p = Mod_Int<mod>(a);
        return is;
    }
};

ll mpow2(ll x, ll n, ll mod) {
    ll ans = 1;
    x %= mod;
    while (n != 0) {
        if (n & 1) ans = ans * x % mod;
        x = x * x % mod;
        n = n >> 1;
    }
    ans %= mod;
    return ans;
}

template <typename T> T modinv(T a, const T& m) {
    T b = m, u = 1, v = 0;
    while (b > 0) {
        T t = a / b;
        swap(a -= t * b, b);
        swap(u -= t * v, v);
    }
    return u >= 0 ? u % m : (m - (-u) % m) % m;
}

ll divide_int(ll a, ll b) {
    if (b < 0) a = -a, b = -b;
    return (a >= 0 ? a / b : (a - b + 1) / b);
}

// const int MOD = 1000000007;
const int MOD = 998244353;
using mint = Mod_Int<MOD>;

// ----- library -------
// ----- library -------

int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    cout << fixed << setprecision(15);

    int si = 2e5 + 10;
    vector<int> spf(si, -1);
    rep2(i, 2, si) {
        if (spf[i] == -1) {
            for (int j = i; j < si; j += i)
                spf[j] = i;
        }
    }
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    auto solve = [&](int i, int j) {
        vector<pii> ans;
        ans.eb(i, j);
        rep(i, n - 2) ans.eb(0, n - 2 - i);
        cout << 0 << endl;
        rep(i, n - 1) cout << ans[i].first + 1 << ' ' << ans[i].second + 1 << '\n';
    };
    rep(i, n) {
        if (a[i] <= 1) {
            solve(i, (i + 1) % n);
            return 0;
        }
    }
    vector<vector<int>> ls(si);
    rep(i, n) {
        int ca = a[i];
        while (ca > 1) {
            int p = spf[ca];
            ls[p].eb(i);
            while (ca % p == 0)
                ca /= p;
        }
    }
    rep(i, si) {
        if (sz(ls[i]) >= 2) {
            solve(ls[i][0], ls[i][1]);
            return 0;
        }
    }
    auto f = [](ll a, ll b) {
        if (gcd(a, b) != 1)
            return 0ll;
        __int128_t x = __int128_t(a) * b - a - b + 1;
        if (x > ll(1e18))
            return ll(2e18);
        else
            return ll(x);
    };
    auto dfs = [&f](vector<ll> a, auto &&dfs) ->pair<ll, vector<pii>> {
        if (sz(a) == 1)
            return pair(a[0], vector<pii>{});
        ll mi = 3e18;
        vector<pii> ord;
        rep(i, sz(a)) rep2(j, i + 1, sz(a)) {
            ll val = f(a[i], a[j]);
            vector<ll> b;
            rep(k, sz(a)) if (k != i && k != j) b.eb(a[k]);
            b.eb(val);
            auto ret = dfs(b, dfs);
            ret.second.eb(i, j);
            if (chmin(mi, ret.first))
                ord = ret.second;
        }
        return pair(mi, ord);
    };
    if (n <= 4) {
        auto [m, ans] = dfs(a, dfs);
        cout << m << endl;
        reverse(all(ans));
        each(e, ans) cout << e.first + 1 << ' ' << e.second + 1 << '\n';
    }
    else {
        exit(1);
        vector<pii> ans;
        rep(i, n) {
            if (a[i] % 2 == 0)
                continue;
            rep2(j, i + 1, n) {
                if (a[j] % 2 == 0)
                    continue;
                rep2(k, j + 1, n) {
                    if (a[k] % 2 == 0)
                        continue;
                    rep2(l, k + 1, n) {
                        if (a[l] % 2 == 0)
                            continue;
                        ans.eb(k, l);
                        ans.eb(i, j);
                        rep(i, n - 3) ans.eb(i, n - 3 - i);
                        cout << 0 << endl;
                        each(e, ans) cout << e.first + 1 << ' ' << e.second + 1 << '\n';
                        return 0;
                    }
                }
            }
        }
    }
}