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#include <bits/stdc++.h>

using namespace std;


int main()
{
    ios_base::sync_with_stdio(0);
   int n;
   cin>>n;
      int il=0;
   for(int i=0;i<n;i++){
    int a;
    cin>>a;
    if(a==1)il++;
   }
   if(il>1)cout<<0<<endl;
   else if(il==1)cout<<1<<endl;
   else cout<<2<<endl;

   cout<<2<<endl<<1<<" "<<2;

}