#!/usr/bin/env python

def read_input():
    with open('input.txt', 'r') as f:
        data = f.read().splitlines()
        return data[0]

def find_longest_match(polymer):
    result = 1
    for x in range(len(polymer)-1):
        if abs(ord(polymer[x]) - ord(polymer[x+1])) != 32:
            break
        result += 1
    return result
            

def retract_polymer(polymer):
    parsing_pos = 0

    while parsing_pos < len(polymer):
        lm = find_longest_match(polymer[parsing_pos:])
        if lm < 2:
            parsing_pos += 1
            continue

        lm = 2
        if parsing_pos == 0:
            polymer = polymer[lm:]
        else:
            polymer = polymer[:parsing_pos] + polymer[lm+parsing_pos:]
            parsing_pos -= 1

    return len(polymer)

l = []
for c in range(ord('a'),ord('z')+1):
    p = read_input()
    if chr(c) not in p:
        continue
    p = p.replace(chr(c), '')
    p = p.replace(chr(c-32), '')
    print("removing characher: {}".format(chr(c)))
    l.append(retract_polymer(p))

print(min(l))