https://school.programmers.co.kr/learn/courses/30/lessons/86491?language=cpp
#include <string>
#include <vector>
using namespace std;
int solution(vector<vector<int>> sizes) {
int answer = 0;
int w = 0; //작은 값
int h = 0; //큰 값
for(int i=0;i<sizes.size();i++){
w = max(w,min(sizes[i].at(0),sizes[i].at(1)));
h = max(h,max(sizes[i].at(0),sizes[i].at(1)));
}
answer = w*h;
return answer;
}