#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

class ElectricCharge {
private:
    double charge, distance;
    
public:
    ElectricCharge(double c, double d) {
        charge = c;
        distance = d;
    }
    
    void computeAndDisplay() {
        const double k = 8.99e9;
        
        if (charge <=0|| distance <=0) {
            cout << "Invalid input";
            return;
        }
        double chargeInCoulombs = (k * chargeInCoulombs * chargeInCoulombs)/ (distance * distance);
        cout << fixed << setprecision(3) << force;
    }
};
int main() {
    double inputCharge, inputDistance;
    if(!(cin>>inputCharge>>inputDistance)) {
        return 0;
    }
    
    ElectricCharge obj(inputCharge,inputDistance);
    obj.computeAndDisplay();
    
    return 0;
}