Rabbits

import sys
import math
sys.setrecursionlimit(10 ** 6)
input = sys.stdin.readline

def fib(a, b):
    fib = []
    for i in range(0, a):
        fib.append(1)
    for i in range(a, b + 1):
        fib.append((fib[-1] + fib[-a]))
    return fib[b]

def fast_exp(m, n):
    if n == 0:
        return [[int(i == j) for i in range(len(m))] for j in range(len(m))]
    g = [[int(i == j) for i in range(len(m))] for j in range(len(m))]
    while n > 1:
        if n % 2 == 1:
            g = MM(g, m)
            n -= 1
        m = MM(m, m)
        n //= 2
    return MM(g, m)


def MM(x, y):
    c = []
    for i in range(0, len(x)):
        temp = []
        for j in range(0, len(y[0])):
            s = 0
            for k in range(0, len(x[0])):
                s += (x[i][k] * y[k][j])
            temp.append(s)
        c.append(temp)
    return c


def create_f_m(a):
    m = []
    fr = [0] * a
    fr[0], fr[-1] = 1, 1
    m.append(fr)
    for i in range(a - 1):
        r = [0] * a
        r[i] = 1
        m.append(r)
    return m
def fib(a, b):
    fib = []
    for i in range(0, a):
        fib.append(1)
    for i in range(a, b + 1):
        fib.append((fib[-1] + fib[-a]))
    return fib[b]


m = create_f_m(2)
a, b = map(int, input().split())

L = -1
R = int(math.log(a) + 10) * 10
# print(R)
while R - L > 1:
    M = (R + L) // 2
    fb = fast_exp(m, M)
    # print(fb[0][0])
    if fb[0][0] >= a:
        R = M
    else:
        L = M

start = R
# print('start', start)
L = start - 1
R = int(math.log(b) + 10) * 10
while R - L > 1:
    M = (R + L) // 2
    fb = fast_exp(m, M)
    if fb[0][0] > b:
        R = M
    else:
        L = M
end = L
# print('end', end)
print(end - start + 1)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED