Rabbits

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int compare(const string& x, const string& y) {
    if (x.size() != y.size()) {
        return x.size() < y.size() ? -1 : 1;
    }
    for (size_t i = 0; i < x.size(); ++i) {
        if (x[i] != y[i]) {
            return x[i] < y[i] ? -1 : 1;
        }
    }
    return 0;
}

string add(const string& x, const string& y) {
    string result;
    int carry = 0, sum = 0;
    int i = x.size() - 1, j = y.size() - 1;
    while (i >= 0 || j >= 0 || carry) {
        sum = carry;
        if (i >= 0) {
            sum += x[i];
            i--;
        }
        if (j >= 0) {
            sum += y[j];
            j--;
        }
        carry = sum / 10;
        result.push_back((sum % 10) + '0');
    }
    reverse(result.begin(), result.end());
    return result;
}

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

    string fib1 = "1", fib2 = "1", fib3;
    int count = 0;

    if (compare("1", a) >= 0 && compare("1", b) <= 0) {
        count++;
    }

    while (true) {
        fib3 = add(fib1, fib2);
        fib1 = fib2;
        fib2 = fib3;

        if (compare(fib3, a) >= 0 && compare(fib3, b) <= 0) {
            count++;
        } else if (compare(fib3, b) > 0) {
            break;
        }
    }

    cout << count << endl;
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: ACCEPTED

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: ACCEPTED

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED