#include<bits/stdc++.h>
#define int long long
using namespace std;
int hs[10];
signed main(){
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	int a,b,ok=0,sum=0;
	cin>>a>>b;
	for(int i=a;i<=b;i++){
		memset(hs,0,sizeof(hs));
		int w=0,g=i;
		ok=0;
		while(1){
			if(g==0)	break;
			hs[g%10]++;
			g/=10;
			w++;
		}
		for(int i=0;i<w;i++){
			if(hs[i]==1)	ok++;
			else	break;
		}
		if(ok==w)	sum++;
	}
	cout<<sum;
	return 0;
}