#include<iostream>
using namespace std;
int main()
{
    int l,r,ge,shi,bai,qian,sum=0;
    cin>>l>>r;
    for(int i=l;i<=r;i++)
    {
        ge=i%10;
        shi=i/10%10;
        bai=i/100%10;
        qian=i/1000;
        if(ge==2||shi==2||bai==2||qian==2)
        sum++;
    }
    cout<<sum;
    return 0;
}