Challenge 9 (Python)

def solveit(file_name = "challenge9_list.txt"):
    f = open(file_name, "r")
    contents = [i[0] for i in f.readlines() if (ord(i[0]) >= ord('a') or ord(i[0]) <= ord('z')) or (ord(i[0]) >= ord('0') or ord(i[0]) <= ord('9'))]
    f.close()
    sumdigit = 0
    alpha = [0 for i in range(26)]
    for i in contents:
        if ord(i) >= ord('0') and ord(i) <= ord('9'):
            sumdigit += int(i)
        else:
            alpha[ord(i) - ord('a')] += 1
    result = "Sum = {0}\n".format(sumdigit)
    for i in range(0,26):
        if alpha[i] != 0:
            result += "'{0}' = {1}\n".format(chr(i + ord('a')), alpha[i])
    return result

if __name__ == "__main__":
    print(solveit())
    input()  # pausa