#include <bits/stdc++.h> using namespace std; #define int long long #define pi pair<int, int> #define vi vector<int> #define vs vector<string> #define vb vector<bool> #define vpi vector<pi> #define pb push_back #define all(a) (a).begin(), (a).end() const int mod = 1e9 + 7; void solve() { int n, m; cin >> n >> m; int a[n], b[n], cnt[n]; multiset<pi> ms; for (int i = 0; i < n; i++) { cin >> a[i]; cnt[i] = 0; ms.insert({0, i}); } for (int i = 0; i < n; i++) { cin >> b[i]; } for (int i = 1; i <= (n * m); i++) { auto p = *ms.begin(); ms.erase(ms.begin()); if (cnt[p.second] == m) { ms.insert({p.first + b[p.second], p.second}); } else { if (a[p.second] > b[p.second]) { ms.insert({p.first + a[p.second], p.second}); cnt[p.second]++; } else { ms.insert({p.first + b[p.second], p.second}); } } } cout << ms.begin()->first << '\n'; } signed main() { ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL); int t = 1; // cin >> t; while (t--) { solve(); } return 0; }