diff --git a/lex.l b/lex.l
index e242919..05cbf4d 100644
--- a/lex.l
+++ b/lex.l
@@ -63,6 +63,11 @@ alphanum	[0-9a-zA-Z_]
 
 \.[Jj][Tt][Aa][Bb]	{ return TJTAB; }
 
+\-{digit}+		{
+			  (void)sscanf(yytext, "%d", &token.ival); 
+			  return NUMBER;
+			}
+
 {digit}+		{
 			  (void)sscanf(yytext, "%d", &token.ival); 
 			  return NUMBER;