How do I get an especific numer from an input in c++?

Having a list of N ordered pairs of the form (A,B)

Example input:

(200,500)
(300,100)
(300,100)
(450,150)
(520,480)

I want to get only the numbers from the input, so that I can use them within my Point structure, and use them to represent the location on a coordinate plane.

Here is my code:

#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <map>
#include <fstream>
using namespace std;

struct Punto
{
    double x,y;
    double distancia;
    double zona;
};

int main()
{
    int n=4;
    Punto arr[n];

    int x, y;
    for(int i=0; i<n; i++){
      cin.ignore(); //(
      std::cin >> x;
      arr[i].x = x;
      std::cout << "Punto " << i << " x " << x << '\n';
      cin.ignore(); //,
      std::cin >> y;
      arr[i].y = y;
      std::cout << "Punto " << i << " y " << y << '\n';
      cin.ignore(); //)
    }


    return 0;
  }

The problem is that this only works with the first entry but not with the following ones.