#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main ()
{     
    int x;
    double n,d,a,b,y=0,i=0,br=0,g=1,f;
    cin>>a>>b>>n>>d;
    x=a;
    do
    {
    do
    {
        x=x/10;
        i++;
    }
    while(x);
    f=i;
    i--;
    do
    {
        g=g*10;
        i--;
    }
    while(i);
    do
    {
        y=y+(g*(x%10));
        x/=10;
        g/=10;
    }
    while(g);
    if(x/y==n/d)br++;
    x++;
    }
    while(x<=b);
    cout<<br<<endl;
    return 0;
}