#include <bits/stdc++.h>
using namespace std;
const char nl = '\n';
void solve() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long a, b, r;
  cin >> a >> b >> r;
  r *= 2;
  b /= r;
  a /= r;
  if (a == 0 || b == 0)
    cout << "Second\n";
  else
    cout << "First\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  solve();
  return 0;
}
