diff --git a/du4/program.c b/du4/program.c
index dc952c7..430e85e 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -25,7 +25,7 @@ for(int c=0;c<count;c++){
     int skip=0,znak=0; 
     for(int idx=0;start[idx]!='\n';idx++){
 	
-	if(start[idx]!='+'&&start[idx]!='-'&&start[idx]!='*'&&start[idx]!='/'){
+	if(start[idx]=='+'||start[idx]=='-'||start[idx]=='*'||start[idx]=='/'){
 	    znak=1;
 	}
 	if((start[idx]<'0'||start[idx]>'9')&&start[idx]!=' '&&start[idx]!='='&&start[idx]!='+'&&start[idx]!='-'&&start[idx]!='*'&&start[idx]!='/'&&start[idx]!='.'){