统计嵌套字典中具有相同值的键的出现次数，如果python中的键出现次数超过x，则删除

nested_dict = {
    'key1': {'sub_key1': 'value1', 'sub_key2': 'value2'},
    'key2': {'sub_key1': 'value2', 'sub_key2': 'value3'},
    'key3': {'sub_key1': 'value1', 'sub_key2': 'value4'}
}

x = 2

count_dict = {}

for key in nested_dict:
    nested_key = nested_dict[key]
    for sub_key in nested_key:
        value = nested_key[sub_key]
        if value in count_dict:
            count_dict[value] += 1
        else:
            count_dict[value] = 1

keys_to_delete = []
for key in count_dict:
    if count_dict[key] > x:
        keys_to_delete.append(key)

for key in keys_to_delete:
    for nested_key in nested_dict:
        if key in nested_dict[nested_key].values():
            del nested_dict[nested_key][list(nested_dict[nested_key].keys())[list(nested_dict[nested_key].values()).index(key)]]