str = ''
data = {}
letters = []
with open('data', 'r') as fp:
    for line in fp:
        if(' -> ' in line):
            pair = line.strip().split(' -> ')
            data[pair[0]] = pair[1]
        elif(len(line) > 1):
            str = line.strip()

for ch in str:
    if(not ch in letters):
        letters.append(ch)
letters.sort()

# # DEBUG(dev):
# print(data)
# print(str)
# print(letters)

for step in range(0, 40):
    print('BEFORE:', str)
    new_str = ''
    for i in range(0, len(str) - 1):
        lookup = str[i:i+2]
        print(lookup)
        if(lookup in data.keys()):
            new_str += str[i] + data[lookup]
        else:
            new_str += str[i]
    new_str += str[-1]
    str = new_str

counts = {}
for ch in str:
    if(ch in counts):
        counts[ch] += 1
    else:
        counts[ch] = 1

counts_list = list(counts.values())
counts_list.sort()

print(counts_list[-1] - counts_list[0])