#include <iostream>
#include <math.h>
#include <algorithm>
#include <iomanip>

using namespace std;

bool isok(double x1, double y1, double x2, double y2, double x3, double y3) {
    if (((x1-x2)*(x3-x2)+(y1-y2)*(y3-y2))==0) return true;
    else return false;
}

int main()
{
    double a1,a2,a3,a4,b1,b2,b3,b4;
    int ans=0;
    cin >> a1 >> b1 >> a2 >> b2 >> a3 >> b3 >> a4 >> b4;
    if (isok(a1,b1,a2,b2,a3,b3)) ans++;
    if (isok(a2,b2,a3,b3,a4,b4)) ans++;
    if (isok(a3,b3,a4,b4,a1,b1)) ans++;
    if (isok(a4,b4,a1,b1,a2,b2)) ans++;
    cout << ans;
}