蜜蜂路线

#include <iostream>
#include <algorithm>
#define SIZE 15001
using namespace std;
int f[SIZE];
int main(){
int n,m,i;
cin>>m>>n;
f[m]=1;
f[m+1]=1;
for(i=m+2;i<=n;i++)
f[i]=f[i-1]+f[i-1];
cout<<f[n]<<endl;
return 0;
}