#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#define maxn 500050using namespace std;long long n,m,a[maxn],ans=0,table[70];bool vis[maxn];void get_table(){    table[0]=1;    for (long long i=1;i<=63;i++)        table[i]=table[i-1]*2;}int main(){    get_table();    scanf("%lld%lld",&n,&m);    for (long long i=1;i<=n;i++) scanf("%lld",&a[i]);    for (long long i=1;i<=n;i++) a[i]^=a[i-1];        for (long long i=63;i>=0;i--)    {        long long ret=0;        for (long long j=1;j<=n-1;j++)        {            long long bit=a[j]&table[i];            if ((!(a[j]&table[i])) && (!vis[j]))                ret++;        }        if ((ret>=m-1) && (!(a[n]&table[i])) && (!vis[n]))        {            for (long long j=1;j<=n;j++)            {                if (a[j]&table[i])                    vis[j]=true;            }        }        else ans|=table[i];    }    printf("%lld\n",ans);    return 0;}