diff --git a/du4/program.c b/du4/program.c
index 918eb39..1cf4302 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -61,7 +61,7 @@ int check(char *str){
         if(str[i]=='='){
             flag=1;
         }
-        if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z')){
+        if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z')||str[i]==','){
             return 0;
         }
     }