#include<iostream> #include<algorithm> using namespace std; int v[5]; int main() { int a , b , c , d; cin >> a >> b >> c >> d; v[1] = a; v[2] = b; v[3] = c; v[4] = d; sort(v+1,v+5); cout <<v[1] * v[2] + v[3]*v[4]; return 0; }