Поляков 24 — 76

f = open('k8-18.txt')
st = f.readline()
m = 0
k = 1
for i in range(len(st) - 1):
    if st[i] == st[i + 1]:
        k += 1
        if k > m:
            m = k
    else:
        k = 1

for i in range(len(st) - 1):
    if st[i] == st[i + 1]:
        k += 1
        if (k == m):
            print(st[i], m)
    else:
        k = 1