#include <iostream> #include <fstream> using namespace std; int main() { ifstream f("input.in"); ofstream g("output.out"); unsigned a,b,c,d,x; f>>a>>b>>c>>d; f.close(); x=a*b+c*d; if(a*c+b*d>x) x=a*c+b*d; if(a*d+b*c>x) x=a*d+b*c; g<<x; g.close(); return 0; }