Rabbits

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<ll> vl;
typedef pair<ll,ll> pl;


typedef long double C;
typedef complex<C> P;
#define X real()
#define Y imag()

#define sz(x) (ll)(x).size()

#define F first
#define S second
#define PB push_back
#define MP make_pair

#define REP(i,a,b) for (ll i = a; i < b; i++)

ll fib(ll n) {
    return (pow(1 + sqrt(5), n) - pow(1 - sqrt(5), n)) / (pow(2,n) * sqrt(5));
}

int main() {
    ll a, b;
    cin >> a >> b;

    ll n = 0;
    ll month = 0;
    if(b == 1) {
        cout << 0 << endl;
        return 0;
    }

    if(a == 2) {
        month++;
    }
    while(true) {
        if((fib(n)+fib(n-1))*2 > a) {
            month++;
        }

        if((fib(n)+fib(n-1))*2 > b) {
            cout << month << endl;
            return 0;
        }
        n++;
    }
    //cout << fib(0) << " " << fib(1) << endl;
}

Test 1

Verdict: TIME LIMIT EXCEEDED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: ACCEPTED

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED