1)
from collections import Counter
f = open('НАЗВАНИЕ ФАЙЛА')
s = f. readline()
x = []
for i in range(len(s)-1):
if s[i] == 'A':
x. append(s[i+1])
print(Counter(x). most_common()[0][0])
2)
from collections import Counter
f = open('НАЗВАНИЕ ФАЙЛА')
s = f. readline()
x = []
for i in range(len(s)-2):
if s[i] == s[i+1]:
x. append(s[i+2])
print(Counter(x). most_common()[0][0])
3)
f = open('НАЗВАНИЕ ФАЙЛА')
s = f. readlines()
c = 0
for i in range(len(s)):
if s[i]. count('E') > s[i]. count('A'):
c += 1
print(c)