Go: package main

import "fmt"

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func main() {
	var a, b, c, d int
	fmt.Scan(&a, &b, &c, &d)
	ans := 10000
	ans = min(ans, abs((a+b)-(c+d)))
	ans = min(ans, abs((a+c)-(b+d)))
	ans = min(ans, abs((a+d)-(b+c)))
	fmt.Println(ans)
}

C++: #include<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(long long i = 0; i < n; i++)
#define REP(i,s,n) for(long long i = (s); i <= (n); i++)
#define repr(i,n) for(long long i = n - 1; i >= 0; i--)
#define REPR(i,s,n) for(long long i = (s); i >= (n); i--)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sumvec(v) accumulate(all(v), 0LL)
#define pb push_back
#define DOUBLE fixed << setprecision(15)
#define OK cerr << "OK\n"
#define OK1 cerr << "OK1\n"
#define OK2 cerr << "OK2\n"
#define sz(s) (long long)s.size()
#define INF ((1LL << 62) - (1LL << 31))
#define zero(x, n) setw(x) << setfill('0') << n
//#define endl '\n'

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<double> vd;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef vector<vd> vvd;
typedef vector<vc> vvc;
typedef vector<vb> vvb;
typedef pair<ll,ll> P;
typedef vector<P> vP;

template<class A, class B>
ostream& operator<<(ostream& ost, const pair<A, B>&p) {
    ost << "{" << p.first << ", " << p.second << "} ";
    return ost;
}

template<class T>
ostream& operator<<(ostream& ost, const vector<T>&v) {
    ost << "{";
    for (int i = 0; i<(int)v.size(); i++) {
        if (i)ost << " ";
        ost << v[i];
    }
    ost << "} \n";
    return ost;
}

template<class A, class B>
ostream& operator<<(ostream& ost, const map<A, B>&v) {
    ost << "{";
    for (auto p:v) {
        ost << "{" << p.first << ", " << p.second << "} ";
    }
    ost << "} ";
    return ost;
}

void out(){cout << "\n";}
template<class T,class... Args>
void out(const T &x,const Args &... args){
    cout << x << " ";
    out(args...);
}

template<typename T>
istream& operator >> (istream& is, vector<T>& vec){
    for(T& e: vec) is >> e;
    return is;
}

template<typename T>
string join(vector<T>& vec, string sep=" "){
    stringstream ss;
    for(int i=0;i<(int)vec.size();i++){
        ss << vec[i] << (i+1==(int)vec.size()?"\n":sep);
    }
    return ss.str();
}

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;}

#define INT(...) int __VA_ARGS__;IN(__VA_ARGS__)
#define LL(...) long long __VA_ARGS__;IN(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;IN(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;IN(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;IN(__VA_ARGS__)
#define LD(...) long double __VA_ARGS__;IN(__VA_ARGS__)

void scan(int& a){ cin >> a; }
void scan(long long& a){ cin >> a; }
void scan(char& a){ cin >> a; }
void scan(double& a){ cin >> a; }
void scan(string& a){ cin >> a; }
void scan(long double& a){ cin >> a; }

void IN(){}
template<class Head,class... Tail> void IN(Head& head,Tail&... tail){ scan(head); IN(tail...); }

void YES(bool b) {cout << ((b)?"YES\n":"NO\n");}
void Yes(bool b) {cout << ((b)?"Yes\n":"No\n");}
void yes(bool b) {cout << ((b)?"yes\n":"no\n");}
void Yay(bool b) {cout << ((b)?"Yay!\n":":(\n");}

const long double pi = acos(-1.0);
const ll mod=1000000007;
//const ll mod=998244353;

ll powmod(ll a,ll b){ll c=1; while(b>0){ if(b&1){ c=a*c%mod; } a=a*a%mod; b>>=1; } return c;}
ll nCrmod(ll n,ll r){ll x=1,y=1; for(ll i=0;i<r;i++) {x=x*(n-i)%mod; y=y*(i+1)%mod; } return x*powmod(y,mod-2)%mod;}
ll gcd(ll a,ll b){ while(b){ ll c=b; b=a%b; a=c; } return a; }
ll lcm(ll a,ll b){ if(!a || !b) return 0; return a*b/gcd(a,b); }
vll divisor(ll x){ vll v; for(int i=1;i*i<=x;i++)if(x%i==0){ v.pb(i);if(i*i!=x)v.pb(x/i); } sort(all(v)); return v; };
map<ll,ll> prime_factor(ll n){ map<ll,ll> m; for(ll i=2;i*i<=n;i++){ while(n%i==0){ m[i]++; n/=i; } } if(n!=1) m[n]=1; return m; }

int main()
{
    vll a(4);
    cin >> a;
    sort(all(a));
    cout << abs(a[0] + a[3] - a[1] - a[2]) << endl;
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <string>
#include <cmath>

using ll = long long;

using namespace std;

int main() {
    int a[4];
    for (int i=0; i<4; i++) cin >> a[i];
    vector<int> ids{0, 1, 2, 3};
    int ans = 100000000;
    do {
        ans = min(ans, abs((a[ids[0]] + a[ids[1]]) - (a[ids[2]] + a[ids[3]])));
    } while (next_permutation(ids.begin(), ids.end()));
    cout << ans << '\n';
    return 0;
}

C++: #include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "unordered_map"
#include "unordered_set"
#include "iomanip"
#include "cmath"
#include "random"
#include "bitset"
#include "cstdio"
#include "numeric"
#include "cassert"
#include "ctime"

using namespace std;

//constexpr long long int MOD = 1000000007;
//constexpr int MOD = 1000000007;
constexpr int MOD = 998244353;
//constexpr long long int MOD = 998244353;
constexpr long double EPS = 1e-8;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	vector<int>v(4);
	for (auto &i : v)cin >> i;
	int ans = 10000;
	for (int i = 0; i < 4; i++) {
		for (int j = i + 1; j < 4; j++) {
			ans = min(ans, abs(accumulate(v.begin(), v.end(), 0) - (v[i] + v[j]) * 2));
		}
	}
	cout << ans << endl;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main() {
    int a[4];
    for (int i = 0; i < 4; ++i) cin >> a[i];
    int ans = (int) 1e9;
    for (int i = 0; i < 4; ++i) {
        for (int j = i + 1; j < 4; ++j) {
            int x = a[i] + a[j];
            int y = 0;
            for (int k = 0; k < 4; ++k) {
                if (k != i && k != j) y += a[k];
            }
            ans = min(ans, abs(x - y));
        }
    }
    cout << ans << '\n';
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)
#define ld long double
const ld pi=3.1415926535897932384626433;


int main()
{
	int a[5];
	rep(i, 4) cin >> a[i];
	sort(a, a+4);
	cout << abs(a[0]+a[3]-a[1]-a[2]) << endl;
	return 0;
}

C++: /**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author aajisaka
 */

#include<bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SPEED ios_base::sync_with_stdio(false);cin.tie(nullptr)
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define all(v) v.begin(), v.end()
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; }

using ll = long long;
using P = pair<ll, ll>;

constexpr long double PI = 3.14159265358979323846264338327950288L;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

class A {
public:
    void solve(istream& cin, ostream& cout) {
      SPEED;
      vector<int> a(4);
      rep(i, 4) cin >> a[i];
      sort(all(a));
      cout << abs(a[3]+a[0]-a[1]-a[2]) << endl;
    }
};

signed main() {
  A solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}