dance hall

# include <iostream>
using namespace std;
#include <iomanip>
#include <math.h>
#include <cmath>

int main()
{
    double lenght;
    do
    {
        cin.clear();
        cin >> lenght;
    }
    while (cin.bad() || lenght < 10 || lenght > 100); //hall lenght
    double width;
    do
    {
        cin.clear();
        cin >> width;
    } while (cin.bad() || width < 10 || width > 100);  //hall width
    double side;
    do
    {
    cin.clear();
    cin >> side;
    }
    while (cin.bad() || side < 2 || side > 20); // wardrobe side
    double hallarea = width * lenght;
    double wardrobearea = side * side; // wardorbe area
    double seatarea = (width * lenght) / 10; //seat area
    double dancerarea = (7000 + 40) * 0.0001;
    double dancersarea = (hallarea - seatarea - wardrobearea) / dancerarea;
    cout << floor(dancersarea) << endl;
    return 0;
}