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