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#include<iostream>
#include<string>
using namespace std;
int main()
{
    int n;
    cin>>n;
    int buf;
    int ile_1 = 0;
    for(int i = 0; i < n; i++)
    {
        cin>>buf;
        if(buf == 1)
            ile_1++;
    }
    if(ile_1 >= 2)
        cout<<0<<endl;
    else if(ile_1 == 1)
        cout<<1<<endl;
    else if(ile_1 == 0)
        cout<<2<<endl;
    cout<<2<<endl<<1<<" "<<2<<endl;
}