#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> veci;
typedef vector<string> vecs;
template<class T,class U> using Hash=unordered_map<T,U>;

#define REP(i, a, n) for(ll i = a; i < n; i++)
#define RREP(i, a, n) for(ll i = n-1; i >= a; i--)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) RREP(i, 0, n)
#define MD 1000000007

template<class T> T read(){T a;cin >> a;return a;}
template<class T> void read(T& a){cin >> a;}
template<class T> void rarr(T a, int n){for(int i = 0; i < n; i++) {cin >> a[i];}}
template<class T> void write(T a){cout << a << endl;}
template<class T> void writes(vector<T> a, const char* c = " "){cout << a[0];for(int i = 1; i < (int)a.size(); i++)cout << c << a[i];cout << endl;;}
void write(double a){cout << fixed << setprecision(12) << a << endl;}
void write(long double a){cout << fixed << setprecision(12) << a << endl;}
template<class T> void warr(T a, int n, const char* c = " "){cout << a[0];for(int i = 1; i < n; i++)cout << c << a[i];cout << endl;}
void split(string s, string delim, veci& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(atoi(s.substr(pos).data()));break;}else {result.push_back(atoi(s.substr(pos, p - pos).data()));}pos = p + delim.size();}}
void split(string s, string delim, vecs& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(s.substr(pos));break;}else {result.push_back(s.substr(pos, p - pos));}pos = p + delim.size();}}
ll gcd(ll a, ll b){while(true){ll k = a % b;if(k == 0)return b;a = b;b = k;}}
ll comb(ll n, ll m){ll p=1;m=min(m,n-m);for(ll i=1;i<=m;i++){p*=n-i+1;p/=i;}return p;}

const int N=13;
int sx,sy,n;
double x[N],y[N],w[N];
double dp[N][1<<N]={0.0};

double culc_bit(int bit){
    double sum=0.0;
    rep(i,n)
        if((bit&(1<<i))>0)sum+=w[i];
    return sum;
}

double culc_time(int cx,int cy,int i,int bit){
    double t=(culc_bit(bit)+100.0)/120.0;
    return t*(fabs(x[i]-cx)+fabs(y[i]-cy));
}

int main(){
    int v[4];
    rep(i,4)cin>>v[i];
    dp[0][0]=0;
    int res=99999;
    REP(i,1,31){
        REP(j,i+1,31){
            REP(k,j+1,31){
                ll ai[3]={i,j,k};
                int dp[31];
                rep(x,31)dp[x]=99999;
                dp[0]=0;
                rep(x,3){
                    rep(y,31-ai[x]){
                        dp[y+ai[x]]=min(dp[y+ai[x]],dp[y]+1);
                    }
                }
                int r=0;
                rep(x,4)r+=dp[v[x]];
                res=min(res,r);
            }
        }
    }
    write(res);
    return 0;
}