#include <bits/stdc++.h>
using namespace std;
#define rep(i,N) for(int i=0;i<int(N);++i)
#define rep1(i,N) for(int i=1;i<int(N);++i)
#define all(a) (a).begin(),(a).end()
#define print(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<_<<", "; cerr<<"]"<<endl; }
#define printpair(v) { cerr<<#v<<": [ "; for(auto _ : v) cerr<<"{"<<_.first<<","<<_.second<<"}"<<", "; cerr<<"]"<<endl; }
#define dump(x) cerr<<#x<<": "<<x<<endl;
#define bit(k) (1LL<<(k))
#define Yes "Yes"
#define No "No"
#define YES "YES"
#define NO "NO"
typedef long long ll;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vec<T>>;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

const int INF = (ll)1e9;
const ll INFLL = (ll)1e18+1;
const ll MOD = (ll)1e9+7;
const double PI = acos(-1.0);
/*
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const string dir = "DRUL";
*/

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    vector<int> a(4);
    rep(i,4)cin >> a[i];
    vector<int> v = {0,1,2,3};
    /*
    昇順にソート済みのvector（またはstring）を入れると
    辞書順で次の並びのvectorに置き換えてくれる
    辞書順最後になったら -1 を返し止まる
    */
    ll ans = INF;
    sort(all(v));
    do{
        ll tmp = abs(a[v[0]] + a[v[1]] - a[v[2]] - a[v[3]]);
        chmin(ans, tmp);
    }while(next_permutation(all(v)));


    cout << ans << endl;
}
