//@formatter:off
#include<bits/stdc++.h>
#define overload4(_1,_2,_3,_4,name,...) name
#define rep1(i,n) for (ll i = 0; i < ll(n); ++i)
#define rep2(i,s,n) for (ll i = ll(s); i < ll(n); ++i)
#define rep3(i,s,n,d) for(ll i = ll(s); i < ll(n); i+=d)
#define rep(...) overload4(__VA_ARGS__,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep1(i,n) for (ll i = ll(n)-1; i >= 0; i--)
#define rrep2(i,n,t) for (ll i = ll(n)-1; i >= (ll)t; i--)
#define rrep3(i,n,t,d) for (ll i = ll(n)-1; i >= (ll)t; i-=d)
#define rrep(...) overload4(__VA_ARGS__,rrep3,rrep2,rrep1)(__VA_ARGS__)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define popcount(x) __builtin_popcountll(x)
#define pb push_back
#define eb emplace_back
#ifdef __LOCAL
#define debug(...) { cout << #__VA_ARGS__; cout << ": "; print(__VA_ARGS__); cout << flush; }
#else
#define debug(...) void(0)
#endif
#define INT(...) int __VA_ARGS__;scan(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;scan(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;scan(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;scan(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;scan(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__;scan(__VA_ARGS__)
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int,int>;
using LP = pair<ll,ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using vd = vector<double>;
using vvd = vector<vector<double>>;
using vs = vector<string>;
using vc = vector<char>;
using vvc = vector<vector<char>>;
using vb = vector<bool>;
using vvb = vector<vector<bool>>;
using vp = vector<P>;
using vvp = vector<vector<P>>;
template<class S,class T> istream& operator>>(istream &is,pair<S,T> &p) { return is >> p.first >> p.second; }
template<class S,class T> ostream& operator<<(ostream &os,const pair<S,T> &p) { return os<<'{'<<p.first<<","<<p.second<<'}'; }
template<class T> istream& operator>>(istream &is,vector<T> &v) { for(T &t:v){is>>t;} return is; }
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) { os<<'[';rep(i,v.size())os<<v[i]<<(i==int(v.size()-1)?"":","); return os<<']'; }
template<class T> void vecout(const vector<T> &v,char div='\n') { rep(i,v.size()) cout<<v[i]<<(i==int(v.size()-1)?'\n':div);}
template<class T> bool chmin(T& a,T b) {if(a > b){a = b; return true;} return false;}
template<class T> bool chmax(T& a,T b) {if(a < b){a = b; return true;} return false;}
void scan(){}
template <class Head, class... Tail> void scan(Head& head, Tail&... tail){ cin >> head; scan(tail...); }
template<class T> void print(const T& t){ cout << t << '\n'; }
template <class Head, class... Tail> void print(const Head& head, const Tail&... tail){ cout<<head<<' '; print(tail...); }
template<class... T> void fin(const T&... a) { print(a...); exit(0); }
struct Init_io {
    Init_io() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        cout.tie(nullptr);
        cout << boolalpha << fixed << setprecision(15);
    }
} init_io;
const string yes[] = {"no","yes"};
const string Yes[] = {"No","Yes"};
const string YES[] = {"NO","YES"};
const int inf = 1001001001;
const ll linf = 1001001001001001001;
//@formatter:on

struct edge {
    int to;
    ll len;
    
    edge(int to, ll l) : to(to), len(l) {}
};

vl dijkstra(int start, const vector<vector<edge>> &v) {
    int n = v.size();
    vl dist(n, linf * 2);
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> q;
    q.emplace(0LL, start);
    dist[start] = 0;
    while (!q.empty()) {
        auto p = q.top();
        q.pop();
        if (dist[p.second] < p.first) continue;
        for (auto e : v[p.second]) {
            if (chmin(dist[e.to], p.first + e.len)) {
                q.emplace(p.first + e.len, e.to);
            }
        }
    }
    return dist;
}

using vve = vector<vector<edge>>;

int main() {
    INT(k);
    LL(n);
    vl a(k), b(k);
    cin >> a >> b;
    if (n < k) fin(a[n]);
    rep(i, k, 2 * k) {
        ll mx = -linf;
        rep(j, k) chmax(mx, min(a[i - k + j], b[j]));
        a.pb(mx);
    }
    n -= k;
    a = vl(a.begin() + k, a.end());
    if (n < k) fin(a[n]);
    ll ok = -linf, ng = linf;
    auto f = [&](ll x) -> bool {
        vi s, t;
        rep(i, k) if (a[i] >= x) s.pb(i);
        rrep(i, k) if (b[i] >= x) t.pb(k - i);
        if (t.empty()) return false;
        vve G(t[0]);
        rep(i, t[0]) {
            rep(j, 1, t.size()) {
                G[i].eb((i + t[j]) % t[0], t[j]);
            }
        }
        auto dist = dijkstra(0, G);
        for (int i : s) {
            if (i > n) continue;
            ll l = n - i;
            if (dist[l % t[0]] <= l) return true;
        }
        return false;
    };
    while (abs(ok - ng) > 1) {
        ll mid = (ng + ok) / 2;
        if (f(mid)) ok = mid;
        else ng = mid;
    }
    fin(ok);
}