#include<iostream>
using namespace std;

void nhap(int n, int a[]){
	for(int i=0; i<n; i++){
		cout << "Phan tu thu " << i << ": ";
		cin >> a[i];
	}
}

void xuat(int n, int a[]){
	cout << "\nIn day so:";
	for(int i=0; i<n; i++){
		cout << " " << a[i];
	}
	cout << endl;
}

int timMax(int n, int a[]){
	int max = a[0];
	for(int i=1; i<n; i++){
		if(a[i] > a[0]) max = a[i];
	}
	return max;
}

bool isChinhPhuong(int c){
	if (c == 1) return true;
	for(int i=2; i<=(c/2); i++){
		if(i*i == c) return true;
	}
	return false;
}

int chinhPhuong(int n, int a[]){
	int b[100];
	int count = 0;
	for(int i=0; i<n; i++){
		if(isChinhPhuong(a[i])){
			count++;
			b[count-1] = a[i];
		}
	}
	int max = -1;
	if(count!= 0) max = timMax(count, b);
	return max;
}

int main(){
	int n;
	do{
		cout << "So phan tu n = "; cin >> n;
	}while(n <= 0 || n >= 20);
	
	int a[n];
	nhap(n, a);
	xuat(n, a);
	cout << endl << "So max = " << timMax(n, a) << endl;
	cout << "So chinh phuong lon nhat: " << chinhPhuong(n, a);
	return 0;
}