#include <iostream>
#include <cmath>

using namespace std;

int main() {

   double x[2]{}, y[2]{}, distance{};

   cin >> x[0] >> y[0] >> x[1] >> y[1];

   distance = sqrt(pow(x[0] - x[1], 2) + pow(y[0] - y[1], 2));
   cout << fixed << distance;

   return 0;

}
#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, C;
  cin >> A >> B >> C;
  if (A == B && B == C) cout << "No" << endl;
  else if (A == B || B == C || C == A) cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}
