C :

#include <stdio.h>
#include <stdlib.h>
int main()
{
	printf("7744");
	return 0;
}
//Author: ITProgrammer

C++ :

#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

int main(){
    for(int i=1100;i<=9999;i++){
    	if(sqrt(i)==(int)sqrt(i)&&i/1000==i/100%10&&i/10%10==i%10){
    		cout<<i<<endl;
		}
	}
}

Python :

def pfs(x):
    for i in range(33, 100):
        if i * i == x:
            return True
    return False


for a in range(1, 10):
    for b in range(0, 10):
        if a != b:
            s = a * 1000 + a * 100 + b * 10 + b
        if pfs(s) is True:
            print(s)