find the min of int value mixed with string value in a nested list in Python

I have a nested li below, I wanted to return a nested li with the string with and min of the int value within the same string value. Any idea?

li=[['a', 10], ['a', 20], ['a', 20], ['a', 40], ['a', 50], ['a', 60]
, ['b', 10], ['b', 20], ['b', 30], ['b', 40]
, ['c', 10], ['c', 10], ['c', 20]]

return

min_li=[['a', 10], ['b', 10], ['c', 10]]

Here is another way you can approach it. First, in a for loop, convert the nested list into a dictionary of key-value pairs, collecting all the values in a list:

li_dict = dict()
for i in li:
  if i[0] in li_dict:
    li_dict[i[0]].append(i[1])
  else:
    li_dict[i[0]] = [i[1]]

li_dict

{'a': [10, 20, 20, 40, 50, 60], 'b': [10, 20, 30, 40], 'c': [10, 10, 20]}

Next, find the minimum value for each key and convert it back into a nested list:

li_min = []
for i in li_dict:
  li_min.append([i, min(li_dict[i])])


li_min

[['a', 10], ['b', 10], ['c', 10]]