#include <bits/stdc++.h>

#define fast ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define output freopen("~/output.txt","w",stdout);
#define input  freopen("~/input.txt","rt",stdin);
#define print(v) for(auto &ele:v)cout<<ele<<" "
#define cin(v) for(auto &ele:v)cin>>ele
#define pp pair<int ,int>
#define all(v) v.begin(),v.end()
#define rv(x) return void(x)
#define ln cout<<"\n";
#define yes cout<<"YES"
#define no cout<<"NO"
#define ll long long
#define vc vector
using namespace std;
int xd[4] = {-1, 0, 1, 0};//,-1,-1, 1, 1};
int yd[4] = {0, 1, 0, -1};//, 1,-1, 1,-1};

//===============================The solution===============================

vector<int> primes;
vector<int> is_prime;
int N = 1e7;

void sievo() {
    is_prime = vector<int>(N, 1);
    for (ll i = 2; i < N; ++i) {
        if (is_prime[i]) {
            primes.push_back(i);
            for (ll j = i * i; j < N; j += i) {
                is_prime[j] = 0;
            }
        }
    }
}

void solve() {
    sievo();
    int l, h, cnt = 0;
    string p;
    cin >> l >> h >> p;
    for (int i = l; i <= h; ++i) {
        string is = to_string(primes[i]);
        if (is.find(p) != -1)cnt++;
    }
    cout << cnt;
}


int main() {
    fast
    int t = 1;
//    cin >> t;
    while (t--) {
        solve();
        ln
    }
}