def sum_of_digits(s):
letters = []
numbers = []
for i in s:
if i.isalpha():
letters.append(i)
elif i.isdigit():
numbers.append(i)
print("The extracted non-digits are: {} ". format(letters), end="\n")
print("The sum of digits operation performs ", "".join(numbers))
sum_of_digits("1aw4")
ZGVmIHN1bV9vZl9kaWdpdHMocyk6CiAgbGV0dGVycyA9IFtdCiAgbnVtYmVycyA9IFtdCgogIGZvciBpIGluIHM6CiAgICBpZiBpLmlzYWxwaGEoKToKICAgICBsZXR0ZXJzLmFwcGVuZChpKQogICAgZWxpZiBpLmlzZGlnaXQoKToKICAgICAgbnVtYmVycy5hcHBlbmQoaSkKICBwcmludCgiVGhlIGV4dHJhY3RlZCBub24tZGlnaXRzIGFyZToge30gIi4gZm9ybWF0KGxldHRlcnMpLCBlbmQ9IlxuIikKICBwcmludCgiVGhlIHN1bSBvZiBkaWdpdHMgb3BlcmF0aW9uIHBlcmZvcm1zICIsICIiLmpvaW4obnVtYmVycykpCgpzdW1fb2ZfZGlnaXRzKCIxYXc0IikK