#include <bits/stdc++.h>
using namespace std;
long long getNumberOfValuesLessThanX(long long X, long long rows,
                                     long long columns) {
  long long lessThanX = X - 1;
  long long sum = 0;
  for (int i = 1; i <= rows; i++) {
    if (columns < lessThanX / i) {
      sum += columns;
    } else {
      sum += lessThanX / i;
    }
  }
  return sum;
}
int main() {
  long long n, m, k;
  cin >> n >> m >> k;
  long long low = 0, high = n * m;
  while (low < high) {
    long long mid = (low + high + 1) / 2;
    if (getNumberOfValuesLessThanX(mid, n, m) < k) {
      low = mid;
    } else {
      high = mid - 1;
    }
  }
  cout << low << endl;
  return 0;
}
