#include<bits/stdc++.h>
using namespace std;
#define ll unsigned long long
ll n,a[1001000],yhh=0;
stack <int> stk;
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		scanf("%lld",&a[i]);
		while(!stk.empty() && a[stk.top()]<=a[i]){
			yhh=yhh^a[stk.top()];
			stk.pop();
		}
		stk.push(i);
		yhh=yhh^i;
		cout<<1<<endl;
		printf("%lld\n", yhh);
	}
	return 0;
}