#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); i--)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;


const int N = 3 << 19;
int isP[N];


int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	cout << fixed << setprecision(15);

	int l, r;
	cin >> l >> r;
	string p;
	cin >> p;
	
	string zeros = "";
	FOR(i, 0, SZ(p) - 1)
		zeros += "0";

	
	fill(isP, isP + N, 1);
	isP[0] = isP[1] = 0;
	vector<string> primes;
	primes.reserve(1e5);
	FOR(pr, 2, N)
	{
		if(!isP[pr])
			continue;
		for(int j = 2 * pr; j < N; j += pr)
			isP[j] = 0;
		primes.PB(zeros + to_string(pr));
	}
	
	int ans = 0;
	FOR(i, l - 1, r)
	{
		bool ok = 0;
		FOR(j, 0, SZ(primes[i]) - SZ(p) + 1)
		{
			if(primes[i].substr(j, SZ(p)) == p)
			{
				ok = 1;
				break;
			}
		}
		if(ok)
			ans++;
	}
	cout << ans << "\n";
	
	
	



	
	return 0;
}