#include <bits/stdc++.h> using namespace std; int main() { int m,n,i,k,s,j,x; cin>>m>>n; for(i=m,x=0;i<=n;i++) { k=i; do{ s=k%10; j=k%100; if(s==4||j==62) { x=x+1; break; } k=k/10; }while (k!=0); } x=n-m+1-x; cout<<x; return 0 ; }