#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

template <typename T>
T kita_masa(const std::vector<T> &c, const std::vector<T> &a, long long n) {
  int k = c.size();
  std::vector<T> coefficient((k << 1) - 1, 0);
  coefficient[0] = 1;
  int now = 0;
  std::vector<std::vector<T>> base(2, std::vector<T>((k << 1) - 1, 0));
  base[now][1] = 1;
  for (; n > 0; n >>= 1) {
    if (n & 1) {
      fill(base[now ^ 1].begin(), base[now ^ 1].end(), 0);
      for (int i = 0; i < k; ++i) for (int j = 0; j < k; ++j) {
        if (coefficient[i] & base[now][j]) base[now ^ 1][i + j] = 1;
      }
      fill(coefficient.begin(), coefficient.end(), 0);
      for (int i = (k << 1) - 2; i >= k; --i) {
        if (base[now ^ 1][i]) coefficient[i] = 1;
        for (int j = 0; j < k; ++j) {
          if (coefficient[i] & c[j]) coefficient[i - k + j] = 1;
        }
      }
      for (int i = 0; i < k; ++i) {
        if (base[now ^ 1][i]) coefficient[i] = 1;
      }
    }
    fill(base[now ^ 1].begin(), base[now ^ 1].end(), 0);
    for (int i = 0; i < k; ++i) for (int j = 0; j < k; ++j) {
      if (base[now][i] & base[now][j]) base[now ^ 1][i + j] = 1;
    }
    now ^= 1;
    for (int i = (k << 1) - 2; i >= k; --i) for (int j = 0; j < k; ++j) {
      if (base[now][i] & c[j]) base[now][i - k + j] = 1;
    }
  }
  for (int i = 0; i < k; ++i) {
    if (coefficient[i] & a[i]) return 1;
  }
  return 0;
}

int main() {
  int k; ll n; cin >> k >> n;
  vector<ll> a(k), b(k);
  REP(i, k) cin >> a[i];
  REP(i, k) cin >> b[i];
  ll lb = min(*min_element(ALL(a)), *min_element(ALL(b))), ub = min(*max_element(ALL(a)), *max_element(ALL(b))) + 1;
  while (ub - lb > 1) {
    ll x = (lb + ub) / 2;
    vector<bool> c(k, false), d(k, false);
    REP(i, k) c[i] = a[i] >= x;
    REP(i, k) d[i] = b[i] >= x;
    (kita_masa(d, c, n) ? lb : ub) = x;
  }
  cout << lb << '\n';
  return 0;
}