#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

long long reverse(long long a){
    long long temp = 0;
    long long base = 1;
    while(a){
        temp = temp*base+a%10;
        base=base*10;
        a/=10;
    }
    return temp;
}
int main() {
    long long a, b, c; cin>>a>>b>>c;
    long long count =0;
    for(long long i=a; i<=b; i++){
        if(abs(reverse(i) - i)%c ==0){
            count++;
        }
    }
    cout<<count<<endl;
    return 0;
}