I want pop out all the large values and its keys in a dictionary, and keep the smallest. Here is the part of my program

```
for key,value in dictionary.items():
    for key1, value1 in dictionary.items(): 
            if key1!= key and value > value1:
                dictionary.pop(key)             
    print (dictionary)  

```

Which results in

```
RuntimeError: dictionary changed size during iteration    

```

How can I avoid this error?