Mesele-F

/*
Author: Kanan Asgarli
*/
#include <bits/stdc++.h>
#define MAX

using namespace std;

double dist(double x1, double y1, double x2, double y2){
    return (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
}
int main()
{
    double x1, y1, x2, y2, x3, y3, x4, y4;
    cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4;
    int say = 0;
    double d1, d2, d3, d4, d5, d6;
    d1 = dist(x1,y1,x2,y2);
    d2 = dist(x2,y2,x3,y3);
    d3 = dist(x3,y3,x4,y4);
    d4 = dist(x1,y1,x4,y4);
    d5 = dist(x1,y1,x3,y3);
    d6 = dist(x2,y2,x4,y4);

    if(d1 + d2 == d5)
        say++;
    if(d2 + d3 == d6)
        say++;
    if(d3 + d4 == d5)
        say++;
    if(d4 + d1 == d6)
        say++;
    cout<<say<<endl;

    return 0;
}