// Problem: T486367 【模拟#4】故障机器人
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/T486367
// Memory Limit: 512 MB
// Time Limit: 1000 ms
// Author: nullptr_qwq
// 
// Powered by CP Editor (https://cpeditor.org)

// 私は猫です

#include<bits/stdc++.h>
#define ull unsigned long long
#define ll long long
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
#define inf 1000000000
#define infll 1000000000000000000ll
#define pii pair<int,int>
#define rep(i,a,b,c) for(int i=(a);i<=(b);i+=(c))
#define per(i,a,b,c) for(int i=(a);i>=(b);i-=(c))
#define F(i,a,b) for(int i=(a);i<=(b);i++)
#define dF(i,a,b) for(int i=(a);i>=(b);i--)
#define cmh(sjy) while(sjy--)
#define lowbit(x) (x&(-x))
#define HH printf("\n")
#define eb emplace_back
#define poly vector<int>
using namespace std;
ll read(){
	ll x=0,f=1;char c=getchar();
	while(c<'0'||c>'9'){if(c=='-') f=-1;c=getchar();}
	while(c>='0'&&c<='9') x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return x*f;
}
const int mod=998244353,maxn=1000005;
inline void chkmax(int &x,const int y){ x=max(x,y); }
inline void chkmin(int &x,const int y){ x=min(x,y); }
inline void chkmax(ll &x,const ll y){ x=max(x,y); }
inline void chkmin(ll &x,const ll y){ x=min(x,y); }
ll a[maxn];
int n,vis[maxn];
void solve(){
	n=read();
	F(i,1,n)a[i]=read(),vis[i]=0;
	ll Xorsum=0;
	F(i,1,n)Xorsum^=a[i];
	if(!Xorsum)return puts("0"),puts("0"),void();
	vector<ll>vec;
	function<ll(int,ll)>upper=[&](int x,ll y){
		return (1ll<<x)-(((1ll<<x)-1)&y);
	};
	dF(i,60,0){
		ll mn=infll,sec=infll;
		int p=-1,q=-1;
		F(j,1,n)if(!vis[j]&&!((a[j]>>i)&1)){
			const ll val=upper(i,a[j]);// let a[j]_i=1,a[j]_{>i}=0
			if(val<mn)q=p,sec=mn,p=j,mn=val;
			else if(val<sec)q=j,sec=val;
		}
		if(~p)vis[p]=1,vec.push_back(a[p]);
		if(~q)vis[q]=1,vec.push_back(a[q]);
	}
	const int siz=vec.size();
	function<ll(int)>calc=[&](int x){
		ll res=0,cur=Xorsum;
		vector<ll>f=vec;
		function<int(int)>oper=[&](int t){
			int p=-1;
			ll mn=infll;
			F(i,0,siz-1)if(!((f[i]>>t)&1)){
				const ll val=upper(t,f[i]);
				if(val<mn)p=i,mn=val;
			}
			if(p<0)return 0;
			res+=mn,cur^=(f[p]^(1ll<<t));
			f[p]^=(((1ll<<t)-1)&f[p])^(1ll<<t);
			return 1;
		};
		if(!((cur>>x)&1)){
			if(!oper(x))return infll;
			if(!oper(x))return infll;
		}
		else if(!oper(x))return infll;
		dF(i,x-1,0)if(((cur>>i)&1)&&!oper(i))return infll;
		return res;
	};
	ll ans=infll;
	dF(i,60,0){
		chkmin(ans,calc(i));
		if((Xorsum>>i)&1)break;
	}
	cout<<ans<<'\n'; puts("0");
}
signed main(){
	read(); int sjy=read();
	cmh(sjy) solve();
}