#include <cstdio>

#define maxn 1010
typedef long long ll;
int a[maxn];
ll s[maxn * maxn];
int main()
{
	int n, k; scanf("%d%d", &n, &k);
	for (int i = 1; i <= n; ++i)
		scanf("%d", a + i);
	int t = 0;
	for (int i = 1; i <= n; ++i)
	{
		ll sum = 0;
		for (int j = i; j <= n; ++j)
			sum += a[j], s[++t] = sum;
	}
	ll ans = 0;
	for (int i = 40; ~i; --i)
	{
		int cnt = 0;
		for (int j = 1; j <= t; ++j)
			if (s[j] & (1ll << i)) ++cnt;
		if (cnt >= k)
		{
			int nt = 0;
			for (int j = 1; j <= t; ++j)
				if (s[j] & (1ll << i)) s[++nt] = s[j];
			t = nt;
			ans |= 1ll << i;
		}
	}
	printf("%lld\n", ans);
	return 0;
}