#include <cstdio>

#include <cstring>

#include <algorithm>

using namespace std;

const int MAX_LEN = 1001, BASE = 10000, CARRY = 4;

struct BigInt

{

private:

	int A[MAX_LEN];

	int Len;

public:

	BigInt()

	{

		memset(A, 0, sizeof(A));

		Len = 0;

	}

	BigInt& operator += (const BigInt& a)

	{

		for (int i = 0; i <= max(Len, a.Len); i++)

		{

			A[i] += a.A[i];

			A[i + 1] += A[i] / BASE;

			A[i] %= BASE;

		}

		if (A[Len + 1])

			Len++;

		return *this;

	}

	BigInt& operator = (const BigInt& a)

	{

		memcpy(A, a.A, sizeof(A));

		Len = a.Len;

		return *this;

	}

	BigInt& operator = (int x)

	{

		memset(A, 0, sizeof(A));

		Len = 0;

		while (x)

		{

			A[Len++] = x%BASE;

			x /= BASE;

		}

		while (Len > 0 && A[Len] == 0)

			Len--;

		return *this;

	}

	BigInt operator +(const BigInt& a)

	{

		BigInt ans = *this;

		return ans += a;

	}

	void Print()

	{

		printf("%d", A[Len]);

		for (int i = Len - 1; i >= 0; i--)

			printf("%0*d", CARRY, A[i]);

	}

};

BigInt& GetF(int n)

{

	static BigInt F[3];

	F[0] = 1;

	F[1] = 1;

	for (int i = 2; i <= n; i++)

		F[i % 3] = F[(i - 1) % 3] + F[(i - 2) % 3];

	return F[n % 3];

}

int main()

{

	int n, m;

	scanf("%d%d", &m, &n);

	GetF(n - m).Print();

	return 0;

}