#include <iostream>

using namespace std;

int main()
{int a,b,c,d,nr1,nr2,nr3,nr4;
nr1=a*b+c*d;
nr2=b*c+d*a;
nr3=c*d+a*b;
nr4=d*a+b*c;
    if(nr1<nr2)
        nr1=nr2;
    if(nr3<nr4)
        nr3=nr4;
        if(nr1<nr3)
        cout<<nr1;
    else cout<<nr3;
    return 0;
}