program zad2;
var s,t,i,n,k:longint;
    x:array[1..100] of integer;
begin
  readln(n);
  for i:=1 to n do readln(x[i]);
  s:=0;
  for i:=1 to n do if x[i]=i then inc(s);
  t:=0;
  for i:=n downto 1 do begin
  inc(k);
  if x[i]=k then inc(t);
  end;
  if (s=n) or (t=n) then writeln(' Not a proof ')
  else writeln(' Cheater ');
end.

Why dont proograme work ? ? ?