#include<stdio.h>
int main()
{
    int train_ordinary,train_unlimited,bus_ordinary,bus_unlimited,total;
    scanf("%d %d %d %d",&train_ordinary,&train_unlimited,&bus_ordinary,&bus_unlimited);
    if(train_ordinary<=train_unlimited)
    {

        if(bus_ordinary<=bus_unlimited)
        {
            total=train_ordinary+bus_ordinary;
        }
        else
        {
            total=train_ordinary+bus_unlimited;
        }
    }
    else
    {
        if(bus_ordinary<=bus_unlimited)
        {
            total=train_unlimited+bus_ordinary;
        }
        else
        {
            total=train_unlimited+bus_unlimited;
        }
    }
    printf("%d\n",total);
    return 0;
}
