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