#include<iostream>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a,b,c,d;
    cin >>a>>b>>c>>d;
    vector<int>v;
    v.push_back(abs(a+b-c-d));
    v.push_back(abs(a+c-b-d));
    v.push_back(abs(a+d-b-c));
    v.push_back(abs(c+b-a-d));
    v.push_back(abs(d+b-a-c));
    v.push_back(abs(c+d-a-b));
    auto min_num=*min_element(v.begin(),v.end());
    cout <<min_num;
    return 0;
}