uses crt;
var n: longint;
begin
clrscr;
    readln(n);
    
    if n = sqr(trunc(sqrt(n))) then writeln('YES')
    else writeln('NO');
readln;
end.

#include <iostream>
#include <math.h>
 
using namespace std;
 
int main(){
    int n;
    cout << "\nn";
    cin >> n;
    int sqr = sqrt(n);
    if(sqr*sqr == n){
        cout << n << " la so chinh phuong\n";
    }
    else {
        cout << n << " khong la so chinh phuong\n";
    }
}

Var n,x: integer;
begin
write('n');
readln(n);
x:=trunc(sqrt(n));
if sqr(x)=n then writeln(n,'la so chinh phuong')
else writeln(n,'khong la so chinh phuong');
readln;
end.