ProcedurProgramavimas_1.07

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

using namespace std;

int main()
{
    long double x1, y1, x2, y2;
    cin >> x1 >> y1;
    cin >> x2 >> y2;

    long double d = sqrtl((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
    cout << fixed << setprecision(2) << d << endl;

    return 0;
}