#include<bits/stdc++.h>
using namespace std;
#define int long long
int shu[1005];
priority_queue<int> q;
signed main(){
    freopen("xor.in","r",stdin);
    freopen("xor.out","w",stdout); 
    int n,k;
    cin>>n>>k;
    for(int i = 1;i<=n;i++){
        cin>>shu[i];
        q.push(shu[i]);
    }
    for(int i = 1;i<=n;i++){
        int zhi=shu[i];
        for(int j = i+1;j<=n;j++){
            zhi=(zhi^shu[j]);
            q.push(zhi);
        }
    }
    int ans=0;
    for(int i = 1;i<=k;i++){
        ans+=q.top();
        q.pop();
    }
    cout<<ans;
    return 0;
}