телепортация

#include <iostream>
#include <fstream>

bool check(int& x, int& y) {
    if (x == y) {
        if (x < y) {
            std::swap(x, y);
        }
        int temp = x - y;
        if (temp % 2 == 0) {
            return true;
        }
        return false;
    }
}

int main() {

    std::ifstream fin("input.txt");
    std::ofstream fout("output.txt");

    int x1, y1, x2, y2;

    fin >> x1 >> y1 >> x2 >> y2;

    if ((x1 + y1) % 2 != (x2 + y2) % 2) {

        fout << '0' << std::endl;
        return 0;

    }

    if (abs(x1 - x2) == abs(y1 - y2)) {
        fout << '1' << std::endl;
        return 0;
    }

    fout << '2' << std::endl;
    return 0;

}