diff --git a/cv3/program.c b/cv3/program.c
index 4cee380..14b341c 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -1,7 +1,8 @@
 #include <stdio.h>
 #include <assert.h>
 #include <stdlib.h>
-/////////////////////////////////////////
+#include <ctype.h>
+
 #define STACK_SIZE 500
 
 struct Stack
@@ -17,13 +18,13 @@ int count_stack(struct Stack* stack);
 
 void push_stack(struct Stack* stack, float value)
 {
-    assert(stack->size < STACK_SIZE); // Program spadne, ak zapisuje mimo
+    assert(stack->size < STACK_SIZE); 
     stack->values[stack->size] = value;
     stack->size += 1;
 }
 float pop_stack(struct Stack* stack)
 {
-    assert(stack->size > 0); // Program spadne, ak číta mimo
+    assert(stack->size > 0); 
     float value = stack->values[stack->size-1];
     stack->size -= 1;
     return value;
@@ -55,17 +56,11 @@ int main()
     do
     {        
       char* p=fgets(buf, 299, stdin);    
-      //printf("{%s}",buf);
-      if(!p)
-      {
-        //printf("==");
-        break;
-      }
-      else
+      if(p)
       {
           char c=buf[0];
           float op1, op2, rez;
-          if(c=='+'||c=='-'||c=='/'||c=='*')   // -45
+          if(c=='+'||c=='-'||c=='/'||c=='*')  
           {
               op2=pop_stack(&mystack);
               op1=pop_stack(&mystack);
@@ -83,17 +78,22 @@ int main()
                                 rez=op1/op2;
                             break;
                   case '*': rez=op1*op2; break;
-              }              //p
+              }              
           }
           else 
           {
-              rez=atof(buf);
+              if(isdigit(c))
+                rez=atof(buf);
+              else
+              {
+                err=1;
+                printf("bad input\n");
+              }
           }
           
           if(!err)
           {
             push_stack(&mystack, rez); 
-            //printf(" %.2f\n", rez);
             print_stack(&mystack);
           }
       }  
@@ -102,4 +102,8 @@ int main()
     if(!err)
         printf("no input\n");
 	return 0;
-}
\ No newline at end of file
+}
+
+
+
+