#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll f[1005];
int main()
{
	ll m,n;
	cin>>m>>n;
	f[m]=1;
	f[m+1]=1;
	for(int i=m+2;i<=n;i++)
	{
		f[i]=f[i-1]+f[i-2];
	}
	cout<<f[n]<<endl;
	return 0;
}