#include <iostream>
using namespace std;

int main() {

   int a, b;
   int count = 0;
   cin >> a >> b;
   for ( int i = a; i < b; i++)
      if( i == 2 || i == 23 || i == 3 || i == 37 || i == 373 || i == 53 ||
         i == 5 || i == 7 || i == 73 || i == 737 ) {
            count++;
         }
   cout << count << endl;
   return 0;
}