#include <bits/stdc++.h>
 
using namespace std;
 
int main()
{	
	ios_base::sync_with_stdio(0);//for optimization.ignore it.
    cin.tie(0);//for optimization.ignore it.
 
    int LD, CD, LV, CV;
 
    cin>>LD>>CD>>LV>>CV;//taking inputs
 
    int d = min(LD,CD);//min()=minimum value
    int v = min(LV,CV);//min()=minimum value
 
    d+=v;//you know what this is
 
    int mini = min(max(LD,CD), max(LV,CV));//max()=maximum value
    int area = min(d, mini)*min(d, mini);
 
    cout<<area<<"\n";//printing output
 
    return 0;
}
 
 

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