#include <iostream>
using namespace std;
int main()
{
    int a,b;
    cin>>a,b;
    int jntm;
    int mtnj=0;
    for(int x =a;x<=b;x++)
    {
        jntm=x;
        while(jntm/10==0)
        {
            if(jntm%10==2)
            {
                mtnj+=1;
            }
            jntm/10;
        }
    }
    cout <<mtnj;
    return 0;
}