#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, r;
  cin >> n >> m >> r;
  vector<int> v(n);
  vector<int> v1(m);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  for (int i = 0; i < m; i++) {
    cin >> v1[i];
  }
  sort(v.begin(), v.end());
  sort(v1.rbegin(), v1.rend());
  if (v[0] > v1[0]) {
    cout << r << endl;
    return 0;
  }
  int cnt = 0;
  cnt += r % v[0];
  cnt += (r / v[0]) * v1[0];
  cout << cnt;
}
