//#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <set>
#include <unordered_set>
#include <queue>
#include <map>
#include <cmath>
#include <climits>
#include <iomanip>
#include <unordered_map>
#include <stdio.h>
#include <stack>
#include <list>
#include "complex"
#include <assert.h>

#define el '\n'
#define ll long long
#define ld long double
using namespace std;
//
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//
//using namespace __gnu_pbds;

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

const int N = 1e5 + 5, mod = 1e9 + 7, MAX = 1e9 + 1, M = 1e5;
long double PI = 3.14159265358979323846;;
#define point  complex<long double>
#define vec(a, b) b-a
#define dot(a, b) (long double)(conj(a)*b).real()
#define cross(a, b) (long double)(conj(a)*b).imag()
#define length(a) (hypot((a).imag(), (a).real()))
#define angle(a) atan2((a).imag(), (a).real())
int h, w;
//char a[201][201];
//int dx[] = {0, 0, -1, 1, 1, -1, -1, 1}, dy[] = {-1, 1, 0, 0, 1, -1, 1, -1};
//int dx[] = {-1, -1, 0, 0, 1, 1}, dy[] = {-1, 0, -1, 1, 0, 1};
//
//bool valid(int i, int j) {
//    return (i < h && i >= 0 && j < w && j >= 0);
//}
//
//bool vis[201][201];

ll mul(ll a, ll b) {
    return ((a % mod) * (b % mod)) % mod;
}

ll add(ll a, ll b) {
    return ((a % mod) + (b % mod)) % mod;
}

ll sub(ll a, ll b) {
    return ((((a + mod) % mod) - ((b + mod) % mod)) + mod) % mod;
}

ll fastpow(ll b, ll p) {
    if (p == 0)
        return 1;
    if (p == 1) {
        return b;
    }
    ll hp = fastpow(b, p / 2);
    ll ans = ((hp % mod) * (hp % mod)) % mod;

    if (p % 2) {
        ans = (ans * b) % mod;
    }

    return ans % mod;
}


bool prime[N];
int spf[N];
vector<string> p;

void sieve() {
    memset(prime, 1, sizeof prime);
    prime[0] = prime[1] = 0;
    for (int i = 0; i <= N; ++i)
        spf[i] = i;

    for (int i = 2; i * i <= N; ++i) {
        if (!prime[i])continue;
        for (int j = i * i; j <= N; j += i) {
            prime[j] = 0;
            spf[j] = min(spf[j], i);
        }
    }
    for (int i = 2; i < N; ++i) {
        if (prime[i])p.push_back(to_string(i));
    }

}

void m() {
    sieve();
   // cout<<p.size()<<' ';
    int l, h;
    cin >> l >> h;
    l--;
    string pp;
    cin >> pp;
    int sz = min(h, (int) p.size());
    int cnt = 0;
    for (int i = l; i < sz; ++i) {
        if (p[i].find(pp) < p[i].size()) {
            cnt++;
            //       cout << p[i] << '\n';
        }
    }
    cout << cnt;

}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    //   cin>>t;
    while (t--) {
        m();
    }

}