#include<bits/stdc++.h>
using namespace std;
int a,b;
int bea_num(int a,int b)
{
    int ans=0,cnt=0;
    for (int i=a;i<=b;i++)
    {
        cnt=0;
        int it=i;
        while (it)
        {
            if (it%10==2)
                cnt++;
            it/=10;
        }
        if (cnt==3)
            ans++;
    }
    return ans;
}
int main()
{
    cin>>a>>b;
    cout<<bea_num(a,b);
    return 0;
}