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#include <iostream>

using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, counter=0,a;
    cin>>n;
    for(int i=0;i<n;++i)
    {
        cin>>a;
        if(a==1)counter++;
    }
    if(counter>1)cout<<0<<"\n";
    else if(counter==1)cout<<1<<"\n";
    else cout<<2<<"\n";
    cout<<2<<"\n"<<1<<" "<<2;
    return 0;
}