#include <bits/stdc++.h>
using namespace std;
int main() {
  double a, b, r;
  cin >> a >> b >> r;
  int plates_horizontal = a / (2 * r);
  int plates_vertical = b / (2 * r);
  int plates = plates_horizontal * plates_vertical;
  if (plates == 0)
    cout << "Second" << endl;
  else
    cout << "First" << endl;
  return 0;
}
