#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

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

    vector<int> use(4);
    for(int i = 0;i<4;i++) cin>>use[i];
    int mx = 0;
    int ans = 1e8;
    for(int i = 0;i<4;i++) mx = max(mx,use[i]);
    for(int i = 1;i<=mx;i++){
        for(int j = i + 1;j<=mx;j++){
            for(int k = j + 1;k<=mx;k++){
                vector<int> dp(mx+1,1e8);
                dp[0] = 0;
                for(int l = 1;l<=mx;l++){
                    if(l-i>=0) dp[l] = min(dp[l],dp[l-i]+1);
                    if(l-j>=0) dp[l] = min(dp[l],dp[l-j]+1);
                    if(l-k>=0) dp[l] = min(dp[l],dp[l-k]+1);
                }
                int cnt = 0;
                for(int l = 0;l<4;l++) cnt += dp[use[l]];
                ans = min(ans,cnt);
            }
        }
    }
    cout<<ans<<endl;
}