#include <string> // std::string #include <iostream> // std::cout #include <sstream> using namespace std; int main() { int a; int b; int c; int d; string tmp; getline(cin, tmp); stringstream ss(tmp); ss >> a; ss >> b; ss >> c; ss >> d; int max = -1; int sum1 = a*b + c*d; if (sum1 > max) max=sum1; int sum2 = a*c + b*d; if (sum2 > max) max=sum2; int sum3 = a*d + c*b; if (sum3 > max) max=sum3; cout<<max; return 0; }