#include <bits/stdc++.h>
using namespace std;
long long n, m, k;
int main() {
  cin >> n >> m >> k;
  long long lo = 1, hi = n * m;
  long long mid, ans = -1;
  while (lo <= hi) {
    mid = (hi + lo) / 2;
    long long cnt = 0;
    for (int i = 1; i <= n; i++) {
      cnt += min(m, (mid - 1) / i);
    }
    if (cnt < k) {
      ans = mid;
      lo = mid + 1;
    } else
      hi = mid - 1;
  }
  cout << ans;
}
