#include <bits/stdc++.h>
using namespace std;
bool check(long long n, long long m, long long k, long long x) {
  long long i, j, ans = 0;
  for (i = 1; i <= min(n, x); i++) {
    ans += min(m, x / i);
    if (ans >= k) return true;
  }
  return false;
}
int main() {
  long long i, j, n, m, k, p, t, ans;
  cin >> n >> m >> k;
  long long h = n * m, l = 1, mid;
  while (l < h) {
    mid = (l + h) / 2;
    if (check(n, m, k, mid) == true)
      h = mid;
    else
      l = mid + 1;
  }
  cout << h << endl;
}
