#include <cstdio>
#include <cstdlib>
#include <algorithm>
using namespace std;
const int N = 100000 + 10;
int n, k, b, s, t;
int a[N], f[N];
int main() {
    freopen("balline.in", "r", stdin);
    freopen("balline.out", "w", stdout);
    scanf("%d %d", &n, &k);
    b = 1 << k;
    for(int i=1; i<=n; i++) {
        scanf("%d", a+i);
        a[i] %= b;
    }
    for(int i=1; i<n; i++) {
        t = a[i];
        for(int j=i+1; j<=n; j++) {
            t ^= a[j];
            if(t == 0)
                s = max(s, j-i+1);
        }
    }
    if(n <= 1)
        s = 0;
    printf("%d\n", s);
    return 0;
}