#include<bits/stdc++.h> 
using namespace std;

#define ll long long
#define foru(a,b,c) for(ll a=b;a<=c;a++)
#define ford(a,b,c) for(ll a=b;a>=c;a--) 

ll n,k,a[500005];
vector<vector<ll>>s;

int main(){
    freopen("xor.in","r",stdin);
    freopen("xor.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin>>n>>k;
    foru(i,1,n){
        cin>>a[i];
    }
    foru(i,1,n){
        foru(j,i,n){
            vector<ll>b;
            foru(k,i,j){
                b.push_back(a[k]);
            }
            s.push_back(b);
        }
    }
    vector<ll>ans;
    for(auto t:s){
        ll xr=0;
        for(auto v:t){
            xr^=v;
        }
        ans.push_back(xr);
    }
    sort(ans.begin(),ans.end(),greater<ll>());
    ll sum=0;
    for(ll i=0;i<k;i++){
        sum+=ans[i];
    }
    cout<<sum;
    return 0;
}