#include <bits/stdc++.h>
using namespace std;

void chmax(int64_t& a, int64_t b){ a = max(a, b); }
void chmin(int64_t& a, int64_t b){ a = min(a, b); }

int main(){
    int K;
    int64_t N;
    cin >> K >> N;
    vector<int64_t> A(2*K), B(K);
    for(int i=0; i<K; i++) cin >> A[i];
    for(int i=0; i<K; i++) cin >> B[i];
    const int64_t INF = 1e18;

    // 最初にA[2K-1]まで求めてしまう
    for(int i=K; i<2*K; i++){
        int64_t mx = -INF;
        for(int j=0; j<K; j++) chmax(mx, min(A[i-K+j], B[j]));
        A[i] = mx;
    }
    if(N < 2*K){
        cout << A[N] << endl;
        return 0;
    }

    // A[N] >= x かどうかを返す
    auto check = [&](int64_t x)->bool{
        vector<int> S, T;
        for(int i=K; i<2*K; i++) if(A[i] >= x) S.push_back(i);
        for(int i=0; i<K; i++) if(B[i] >= x) T.push_back(K-i);
        if(T.size() == 0) return false;

        // ダイクストラ法
        int m = T[0];
        vector<int64_t> D(m, INF+1);
        for(int s : S) chmin(D[s%m], s);
        vector<bool> done(m);
        while(true){
            int s = -1;
            for(int i=0; i<m; i++) if(!done[i]) if(s == -1 || D[s] > D[i]) s = i;
            if(s == -1) break;
            for(int t : T) chmin(D[(s+t)%m], D[s] + t);
            done[s] = true;
        }

        return (D[N%m] <= N);
    };

    int64_t ok = -INF, ng = INF+1;
    while(ng-ok>1){
        int64_t mid = (ok+ng)/2;
        (check(mid) ? ok : ng) = mid;
    }
    cout << ok << endl;
    return 0;
}