#include <bits/stdc++.h>
// #pragma GCC optimize ("O3")
// #pragma GCC target ("sse4")
using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int,int> PII;

#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i,a,b) for (int i=(a); i<(b); ++i)
#define FORD(i,a,b) for (int i=(a)-1; i>=(b); --i)

#define pb push_back
#define mp make_pair
#define st first
#define nd second

int main() {
  int N;
  scanf("%d", &N);
  int ones = 0;
  REP(i,N) {
    int d;
    scanf("%d", &d);
    ones += (d == 1);
  }
  printf("%d\n2\n1 2\n", max(0, 2 - ones));
}