#include <iostream>

using namespace std;

int main() {
    double ax, ay, a;
    cin >> ax >> ay >> a;

    if (abs(ax) > abs(a)) {
        cout << boolalpha << (abs(ax) < abs(ay));
    } else {
        cout << boolalpha << (ax * ax + ay * ay <= a * a);
    }

    return 0;
}