diff --git a/du4/program.c b/du4/program.c
index 9e73590..f174d6d 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -63,7 +63,7 @@ int main()
     	sscanf(new_str,"%lf%c%lf%s%lf",&first,&c,&second,ravno,&res);
     
     
-    	if(c=='E'||first==-5||second==-5||res==-5||(c!=43&&c!=42&&c!=45&&c!=47||(strlen(ravno)==1&&ravno[0]=='='))){
+    	if(c=='E'||first==-5||second==-5||res==-5||(c!=43&&c!=42&&c!=45&&c!=47||(strlen(ravno)!=1||ravno[0]!='='))){
     	    printf("CHYBA\n");
           	continue;
     	}