#include <bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>

#define fa ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(0);
typedef long long ll;
typedef long double ld;
typedef double d;
typedef unsigned long long ull;
#define all(v) ((v).begin()),((v).end())
#define rall(v) ((v).rbegin()),((v).rend())
using namespace std;
using namespace __gnu_pbds;
template<typename T>
using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;


template<typename T = ll>
istream &operator>>(istream &in, vector<T> &v) {
    for (auto &x: v) in >> x;
    return in;
}

template<typename T = ll>
ostream &operator<<(ostream &out, const vector<T> &v) {
    for (const T &x: v) out << x << " ,";
    return out;
}

const int N = 5*1e6 + 5;

int prime[N];
signed main() {
#ifndef ONLINE_JUDGE
    freopen("i.txt", "r", stdin);
    freopen("o.txt", "w", stdout);
#endif
    fa

    ll T = 1, k;
    // cin >> T;


    while (T--) {
        int l, r;
        cin >> l >> r;

        string s;
        cin >> s;

        for (int i = 0; i < N; i++) {
            prime[i] = 1;
        }

        prime[0] = prime[1] = 0;

        for (int i = 2; i < N; i++) {

            if (!prime[i]) continue;
            for (int j = i + i; j < N; j += i) {
                prime[j] = 0;
            }
        }

        vector<int> v;

        int cnt = 0;
        for (int i = 0; i < N; i++) {
            if (prime[i]) {
                v.push_back(i);
            }
        }

        int ans = 0;
        l--, r--;

        for (int i = l; i <= r; i++) {

            string p = to_string(v[i]);

            if (p.find(s) != string::npos) {
                ans++;
            }
        }

        cout <<ans << endl;

    }


}