#include <bits/stdc++.h>
using namespace std;
#define incII(i, l, r) for(decay_t<decltype(r)> i = (l)    ; i <= (r); i++)
#define incIX(i, l, r) for(decay_t<decltype(r)> i = (l)    ; i <  (r); i++)
#define incXI(i, l, r) for(decay_t<decltype(r)> i = (l) + 1; i <= (r); i++)
#define incXX(i, l, r) for(decay_t<decltype(r)> i = (l) + 1; i <  (r); i++)
#define decII(i, l, r) for(decay_t<decltype(r)> i = (r)    ; i >= (l); i--)
#define decIX(i, l, r) for(decay_t<decltype(r)> i = (r) - 1; i >= (l); i--)
#define decXI(i, l, r) for(decay_t<decltype(r)> i = (r)    ; i >  (l); i--)
#define decXX(i, l, r) for(decay_t<decltype(r)> i = (r) - 1; i >  (l); i--)
#define inc(i, n)  incIX(i, 0, n)
#define dec(i, n)  decIX(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define dec1(i, n) decII(i, 1, n)
auto inII = [](auto a, auto l, auto r) -> bool { return (l <= a && a <= r); };
auto inIX = [](auto a, auto l, auto r) -> bool { return (l <= a && a <  r); };
auto inXI = [](auto a, auto l, auto r) -> bool { return (l <  a && a <= r); };
auto inXX = [](auto a, auto l, auto r) -> bool { return (l <  a && a <  r); };
auto setmin   = [](auto & a, auto b) -> bool { return (b <  a ? a = b, true : false); };
auto setmax   = [](auto & a, auto b) -> bool { return (b >  a ? a = b, true : false); };
auto setmineq = [](auto & a, auto b) -> bool { return (b <= a ? a = b, true : false); };
auto setmaxeq = [](auto & a, auto b) -> bool { return (b >= a ? a = b, true : false); };
using LL = long long int;
using LD = long double;
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define MT make_tuple
#define FI first
#define SE second
#define FR front()
#define BA back()
#define ALL(a) begin(a), end(a)
#define RALL(a) rbegin(a), rend(a)
#define RV(a) reverse(ALL(a))
#define ST(a) sort(ALL(a))
#define RST(a) sort(RALL(a))
#define SC static_cast
#define SI(a) SC<int>(a.size())
#define SL(a) SC<LL>(a.size())
#define RF(e, ...) for(auto && e: __VA_ARGS__)
#define SF(a, ...) for(auto && [__VA_ARGS__]: a)
#define until(...) while(not(__VA_ARGS__))
#define if_not(...) if(not(__VA_ARGS__))
#define ef else if
#define UR assert(false)
template<typename A>             istream & operator>>(istream & is, vector<A>          & v);
template<typename A>             ostream & operator<<(ostream & os, vector<A>    const & v);
template<typename A, size_t N>   istream & operator>>(istream & is, array<A, N>        & a);
template<typename A, size_t N>   ostream & operator<<(ostream & os, array<A, N>  const & a);
template<typename A, typename B> istream & operator>>(istream & is, pair<A, B>         & p);
template<typename A, typename B> ostream & operator<<(ostream & os, pair<A, B>   const & p);
template<typename ... A>         istream & operator>>(istream & is, tuple<A ...>       & t);
template<typename ... A>         ostream & operator<<(ostream & os, tuple<A ...> const & t);
template<int I = 0, typename T> void tin_ (istream & is, T       & t) { if constexpr(I < tuple_size<T>::value) { is >> get<I>(t); tin_<I + 1>(is, t); } }
template<int I = 0, typename T> void tout_(ostream & os, T const & t) { if constexpr(I < tuple_size<T>::value) { if(I != 0) { os << " "; } os << get<I>(t); tout_<I + 1>(os, t); } }
template<typename A>             istream & operator>>(istream & is, vector<A>          & v) { for(auto && e: v) { is >> e; } return is; }
template<typename A>             ostream & operator<<(ostream & os, vector<A>    const & v) { string ss; for(auto && e: v) { os << ss << e; ss = " "; } return os; }
template<typename A, size_t N>   istream & operator>>(istream & is, array<A, N>        & a) { for(auto && e: a) { is >> e; } return is; }
template<typename A, size_t N>   ostream & operator<<(ostream & os, array<A, N>  const & a) { string ss; for(auto && e: a) { os << ss << e; ss = " "; } return os; }
template<typename A, typename B> istream & operator>>(istream & is, pair<A, B>         & p) { return is >> p.first >> p.second; }
template<typename A, typename B> ostream & operator<<(ostream & os, pair<A, B>   const & p) { return os << p.first << " " << p.second; }
template<typename ... A>         istream & operator>>(istream & is, tuple<A ...>       & t) { tin_ (is, t); return is; }
template<typename ... A>         ostream & operator<<(ostream & os, tuple<A ...> const & t) { tout_(os, t); return os; }
auto * IS = & cin;
auto * OS = & cout;
template<typename ... A> void in(A & ... a) { (* IS >> ... >> a); }
#define IN(...) __VA_ARGS__; in(__VA_ARGS__)
template<typename A                > auto make_v(A a) { return a; }
template<typename A, typename ... M> auto make_v(A a, int n, M ... m) { return vector(n, make_v(a, m ...)); }
template<typename A, typename ... N> auto read_v(N ... n) { auto a = make_v(A { }, n ...); in(a); return a; }
void                                      out_([[maybe_unused]] string const & s) { }
template<typename A                > void out_([[maybe_unused]] string const & s, A const & a) { * OS << a; }
template<typename A, typename ... B> void out_(                 string const & s, A const & a, B const & ... b) { * OS << a << s; out_(s, b ...); }
auto outF  = [](string const & s, string const & t, auto const & ... a) { out_(s, a ...); * OS << t << flush; };
auto outN  = [](auto const & ... a) { outF(""  , ""  , a ...); };
auto outS  = [](auto const & ... a) { outF(" " , " " , a ...); };
auto outL  = [](auto const & ... a) { outF("\n", "\n", a ...); };
auto outSN = [](auto const & ... a) { outF(" " , ""  , a ...); };
auto outNL = [](auto const & ... a) { outF(""  , "\n", a ...); };
auto outSL = [](auto const & ... a) { outF(" " , "\n", a ...); };
auto out   = outSL;
template<typename A                > void disp_(A const & a) { * OS << a; }
template<typename A, typename ... T> void disp_(A const & a, string const & s, T const & ... t) { string ss; for(auto && e: a) { * OS << ss; ss = s; disp_(e, t ...); } }
auto dispI = [](auto const & a, auto const & s, auto const & ... t) { disp_(a, t ...); * OS << s << flush; };
auto dispT = [](auto const & a, auto const & s, auto const & ... t) { for(auto && e: a) { disp_(e, t ...); * OS << s; } * OS << flush; };
auto dispL = [](auto const & a,                 auto const & ... t) { dispT(a, "\n", t ...); };
struct OS_init { OS_init() { * OS << boolalpha << fixed << setprecision(20); } } os_init_;

// ---- ----

template<typename T> string tostr(T n, int base = 10, int len = 0, bool cap = true) {
	assert(inII(base, 2, 36));
	string sign = (n < 0 ? "-" : ""), str;
	n = abs(n);
	do {
		int d = n % base;
		str += (d < 10 ? '0' + d : (cap ? 'A' : 'a') + (d - 10));
		n /= base;
	} while(n || SI(str) < len);
	RV(str);
	return sign + str;
}

int main() {
	auto f = [](LL a, LL b) -> LL {
		return (gcd(a, b) == 1 ? (a - 1) * (b - 1) : 0);
	};
	
	int IN(n);
	auto a = read_v<LL>(n);
	
	if(n == 2) {
		out(f(a[0], a[1]));
		out(1, 2);
		exit(0);
	}
	
	vector<int> E, O;
	inc(i, n) { (a[i] % 2 == 0 ? E : O).PB(i); }
	
	if(SI(E) >= 2) {
		out(0);
		out(E[0] + 1, E[1] + 1);
		inc(i, n - 2) { out(1, n - 1 - i); }
	}
	ef(SI(E) == 1 && SI(O) >= 2) {
		out(0);
		out(O[0] + 1, O[1] + 1);
		if(O[1] < E[0]) { E[0]--; }
		if(O[0] < E[0]) { E[0]--; }
		out(E[0] + 1, n - 1);
		inc(i, n - 3) { out(1, n - 2 - i); }
	}
	ef(SI(O) >= 4) {
		out(0);
		out(O[2] + 1, O[3] + 1);
		out(O[0] + 1, O[1] + 1);
		inc(i, n - 3) { out(1, n - 2 - i); }
	}
	else {
		assert(SI(E) == 0 && SI(O) == 3);
		vector<pair<LL, string>> v = {
			{ f(f(a[0], a[1]), a[2]), "1 2" },
			{ f(f(a[0], a[2]), a[1]), "1 3" },
			{ f(f(a[1], a[2]), a[0]), "2 3" },
		};
		ST(v);
		out(v[0].FI);
		out(v[0].SE);
		out(1, 2);
	}
}