#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pl pair<ll, ll>
#define pi pair<int, int>
#define minpq priority_queue<ll, vector<ll>, greater<ll>>
using namespace std;

#if 1
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '['; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "]";}
void _print() {cerr << endl << flush;}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "*["<<__LINE__<<"]\t"<< #x << " = "; _print(x)
#endif

const ll mod = 1e9 + 7;

template<typename T> bool chkmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
ll gcd(ll a, ll b) {if(b == 0){return a;} return gcd(b, a % b);}

const int maxn = 2000020;
int p[maxn];
vector<string> primes;

void sieve(){
	for (int i = 0; i < maxn; i ++) p[i] = i;
	for (int i = 2; i < maxn; i ++){
		for (int j = i + i; j < maxn; j += i){
			p[j] = i;
		}
	}
}

bool issubstr(string s, string t){
	if (t.size() > s.size()) return false;
	for (int i = 0; i <= s.size() - t.size(); i ++){
		if (s.substr(i, t.size()) == t) return true;
	}
	return false;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	sieve();
	for (int i = 2; i < maxn; i ++) if (p[i] == i) primes.push_back(to_string(i));
	int l, h; cin >> l >> h; l --; h --;
	string p; cin >> p;
	int ans = 0;
	for (int i = l; i <= h; i ++) if (issubstr(primes[i], p)) ans ++;
	cout << ans;
}