upd cv3

cv3/program.c

@@ -81,11 +81,15 @@ int main(int argc, char const *argv[])
         {
             break;
         }
-        if(isalpha(buf) != 0)
+        for (int i = 0; i < strcspn(buf, "\n"); i++)
+        {
+            if(isalpha(buf[i]) != 0)
             {
                 printf("bad input\n");
                 return 0;
             }
+        }
+        
         buf[strcspn(buf, "\n")] = '\0';
         if(!check_op(buf[0]))
         {