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#include <iostream>

using namespace std;

int main()
{
    int a,l=0,k;
    cin>>a;
    for(int i=0; i<a; ++i){
        cin>>k;
        if(k==1){
            l++;
        }
    }
    if(l>=2){
        cout<<0<<endl;
    }else if(l==1){
        cout<<1<<endl;
    }else if(l==0){
        cout<<2<<endl;
    }
    cout<<2<<endl;
    cout<<1<<" "<<2;
}