1 files changed, 5 insertions, 4 deletions
diff --git a/others/volume1/018.pas b/others/volume1/018.pas
index 05fd7e9..053095c 100644
--- a/others/volume1/018.pas
+++ b/others/volume1/018.pas
@@ -1,11 +1,12 @@
+uses cmath;
+
 var
   n: int64;
 
 begin
   readln(n);
-  if (n < 0) or
-     (sqr(trunc(sqrt(n))) <> n) then
-    writeln('NO')
-  else
+  if issquare(n) then
     writeln('YES')
+  else
+    writeln('NO')
 end.