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


string add(string a,string b) 
{
    vector<int> na,nb;
    
    for (char s : a) 
    {
        na.push_back(s-'0');
    }
    for (char s : b) 
    {
        nb.push_back(s - '0');
    }

    
    reverse(na.begin(), na.end());
    reverse(nb.begin(), nb.end());

    
    while (na.size()<nb.size()) 
    {
        na.push_back(0);
    }
    while (nb.size()<na.size()) 
    {
        nb.push_back(0);
    }

    vector<int> res;
    int k=0;
    for (size_t i=0;i<na.size();i++) 
    {
        int sum=na[i]+nb[i]+k;
        res.push_back(sum%10);
        k=sum/10;
    }

    

    if (k) 
    {
        res.push_back(k);
    }

   
    string ans;
    for (int s:res) 
    {
        ans.push_back(s + '0');
    }

    
    reverse(ans.begin(), ans.end());

    return ans;
}

int m,n;
int main() 
{
    cin>>m>>n;
    
    string a[10005]={"0","1","1"};
    for(int i=3;i<=n-m+1;i++)
    {
        a[i]=add(a[i-1],a[i-2]);
    } 
    cout<<a[n-m+1];
    return 0;
}