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#include<bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define REP(i, a) FOR(i, 0, a - 1)
#define ST first
#define ND second
#define V vector
#define RS resize
#define EB emplace_back
#define ALL(a) a.begin(), a.end()
#define S(a) (int)a.size()

template<class T> void db(T a) { cerr << a; }
template<class L, class R> void db(pair<L, L> a) { cerr << "(" << a.ST << ", " << a.ND << ")"; }
template<class T> void db(V<T> v) { cerr << "{"; REP(i, S(v)) cerr << (i != 0 ? ", " : ""), db(v[i]); cerr << "}"; }
template<class T> void dump(const char *s, T a) { cerr << s << ": "; db(a); cerr << "\n"; }
template<class T, class... TS> void dump(const char *s, T a, TS... x)
{ while(*s != ',') cerr<< *s++; cerr << ": "; db(a); dump(s + 1, x...); }

#ifdef DEBUG
#define DB(...) dump(#__VA_ARGS__, __VA_ARGS__); 
#else
#define DB(...)
#endif

using LL = long long;
using PII = pair<int, int>;
using VI = V<int>;
using VLL = V<LL>;
using VVI = V<VI>;
using VPII = V<PII>;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n, ans = 2, a;
    cin >> n;
    REP(i, n)
    {    
    	cin >> a;
    	if(a == 1 && ans != 0) ans--;
    }
    cout << ans << "\n2\n1 2\n";
}