Program Kvadrat_Chisla;
uses wincrt;
var
s: string;
ch: char;
i,Code: integer;
begin
read(s);
ch:=s[length(s)];
val(ch,i,Code);
if Code <> 0 then
write('Poslednii simvol ne cifra!')
else
begin
str(i*i,s);
ch:=s[length(s)];
write(ch);
end;
end.