#include<bits/stdc++.h>
using namespace std;
int cmp(int a , int b = 0)
{
while(a != 0)
{
if(a % 10 == 2)
{
b++;
}
a /= 10;
}
return b;
}
int main()
{
int l , r , sum = 0 , num = 0;
cin >> l >> r;
for(int i = l;i <= r;i++)
{
if(cmp(i , sum) == 3)
{
num++;
}
}
cout << num;
return 0;
}
