#include<bits/stdc++.h>
#define r(a) scanf("%d",&a)
#define rll(a) scanf("%lld",&a)
#define rull(a) scanf("%llu",&a)
#define f(i,l,r) for(int i=l;i<=r;i++)
#define F(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int a,b;
int ff(int i){
	int sum=1;
	int t=sqrt(i);
	for(int j=2;j<=t;j++){
		if(i%j==0){
			sum+=j;
			if(i%(i/j)==0) sum+=(i/j);
		}
	}
	return sum;
}
signed main(){
	r(a);r(b);int ans=0;
	f(i,a,b){
		int p=ff(i);
		if(i<p&&ff(p)==i&&i!=p) ans++;
	}
	cout<<ans;
	return 0;
}