#include <bits/stdc++.h>
using namespace std;
const int inf = 2147483647;
const long long llinf = 9223372036854775807LL;
int main() {
  long long n, m, k;
  cin >> n >> m >> k;
  if (n > m) swap(n, m);
  long long l = 1, r = n * m + 1;
  while (l < r) {
    long long res = 0;
    long long mid = (l + r) / 2;
    for (int i = 1; i <= n; i++) {
      res += min(m, mid / i);
    }
    if (res < k)
      l = mid + 1;
    else
      r = mid;
  }
  cout << r;
  return 0;
}
