#include <bits/stdc++.h>
#define For(i, a, b) for(int (i)=(int)(a); (i)<(int)(b); ++(i))
#define rFor(i, a, b) for(int (i)=(int)(a)-1; (i)>=(int)(b); --(i))
#define rep(i, n) For((i), 0, (n))
#define rrep(i, n) rFor((i), (n), 0)
#define fi first
#define se second
using namespace std;
typedef long long lint;
typedef unsigned long long ulint;
typedef pair<int, int> pii;
typedef pair<lint, lint> pll;
template<class T> bool chmax(T &a, const T &b){if(a<b){a=b; return true;} return false;}
template<class T> bool chmin(T &a, const T &b){if(a>b){a=b; return true;} return false;}
template<class T> T div_floor(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>=0 ? a/b : (a+1)/b-1;
}
template<class T> T div_ceil(T a, T b){
    if(b < 0) a *= -1, b *= -1;
    return a>0 ? (a-1)/b+1 : a/b;
}

constexpr lint mod = 1e9+7;
constexpr lint INF = mod * mod;
constexpr int MAX = 200010;

int main(){
    int v[4];
    rep(i, 4) scanf("%d", &v[i]);
    int a[3], ans = MAX;
    for(a[0]=1; a[0]<=30; ++a[0]){
        for(a[1]=a[0]+1; a[1]<=30; ++a[1]){
            for(a[2]=a[1]+1; a[2]<=30; ++a[2]){
                int dp[4][35];
                rep(i, 4)rep(j, 35) dp[i][j] = MAX;
                dp[0][0] = 0;
                rep(i, 3)rep(j, 35)if(dp[i][j] < MAX){
                    chmin(dp[i+1][j], dp[i][j]);
                    if(j+a[i] < 35) chmin(dp[i][j+a[i]], dp[i][j] + 1);
                }

                int tmp = 0;
                rep(i, 4) tmp += dp[3][v[i]];
                chmin(ans, tmp);
            }
        }
    }
    printf("%d\n", ans);
}