#include <bits/stdc++.h>

using namespace std;
#define int long long int
const int N = 8e7+5, MOD = 1e9 + 7; // 

#define nl '\n'
#define rv return void
#define Tests int test_cases; cin >> test_cases; for(int tc=1; tc<=test_cases; tc++)
#define EidMubarak ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);

vector<bool> prime(N, true);
vector<int> primes;

void sieve() {
    prime[0] = prime[1] = false;
    for (int p = 2; p <= N / p; p++) {
        if (prime[p]) {
            for (int i = p * p; i < N; i += p) {
                prime[i] = false;
            }
        }
    }
    for (int i = 2; i < N; i++) {
        if (prime[i]) {
            primes.emplace_back(i);
        }
    }
}

string s, t;

bool can(int x) {
    t = to_string(x);
    return (t.find(s) != -1);
}

signed main() {
    EidMubarak
    // y3ni_mht3dee4();
    sieve();
    int l, r, ans = 0;
    cin >> l >> r >> s;
    for (int i = l - 1; i < r; i++)
        if (can(primes[i]))
            ans++;
    cout << ans << nl;
}