#!/usr/bin/env python3
from pathlib import Path
from collections import Counter, defaultdict


def part_1(input):
    result = 0
    template = input.pop(0).strip()
    input.pop(0)
    rules = {k.strip(): v.strip()
             for line in input for k, v in [line.strip().split('->')]}
    counts = defaultdict(int)
    for i in range(len(template) - 1):
        counts[template[i: i + 2]] += 1
    for _ in range(10):
        tmp_cnts = counts.copy()
        for k in tmp_cnts:
            if k in rules:
                c = tmp_cnts[k]
                counts[k] -= c
                counts[k[0] + rules[k]] += c
                counts[rules[k] + k[1]] += c
    char_counts = defaultdict(int)
    for k in counts:
        char_counts[k[0]] += counts[k]
        char_counts[k[1]] += counts[k]
    char_counts[template[0]] += 1
    char_counts[template[-1]] += 1
    for k in char_counts:
        char_counts[k] //= 2
    char_counts = sorted(char_counts.items(),
                         key=lambda kv: kv[1])
    result = char_counts[-1][1] - char_counts[0][1]
    print("Part 1 result:", result)


def part_2(input):
    result = 0
    template = input.pop(0).strip()
    input.pop(0)
    rules = {k.strip(): v.strip()
             for line in input for k, v in [line.strip().split('->')]}
    counts = defaultdict(int)
    for i in range(len(template) - 1):
        counts[template[i: i + 2]] += 1
    for _ in range(40):
        tmp_cnts = counts.copy()
        for k in tmp_cnts:
            if k in rules:
                c = tmp_cnts[k]
                counts[k] -= c
                counts[k[0] + rules[k]] += c
                counts[rules[k] + k[1]] += c
    char_counts = defaultdict(int)
    for k in counts:
        char_counts[k[0]] += counts[k]
        char_counts[k[1]] += counts[k]
    char_counts[template[0]] += 1
    char_counts[template[-1]] += 1
    for k in char_counts:
        char_counts[k] //= 2
    char_counts = sorted(char_counts.items(),
                         key=lambda kv: kv[1])
    result = char_counts[-1][1] - char_counts[0][1]
    print("Part 2 result:", result)


input = list()
p = Path(__file__).with_name('input.txt')
with open(p) as f:
    input = f.readlines()
    part_1(input.copy())
    part_2(input.copy())