dem23.n25_NoneType - WHY???

f = open('26.txt')
n = int(f.readline())
lines = f.readlines()
#print(n)
#print(lines[:20])
a = [int(i) for i in lines]
print(type(a))
#print(a[:20])
a = a[::-1]
print(type(a))

i = 0
k = 1
lst = 0

mx = a[0]
while i + 1 < n:
    i += 1
    if abs(a[i] - a[lst]) >= 3:
        k += 1
        lst = i
        mx = a[i]

print(k,mx)