#include<bits/stdc++.h> using namespace std; int main(){ int n,m,count=0,a,b; cin>>n>>m; for(int i=n;i<=m;i++){ a=i; while(a!=0){ b = a%10; a = a/10; if(b==4){ count++; break; } else if(b==2){ if(a%10==6){ count++; break; } } } } cout<<m-n+1-count; return 0; }