#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <stdbool.h>

void Sieve(int m, int **primes, int *prime_count) {
    bool *is_prime = malloc((m + 1) * sizeof(bool));
    for (int i = 0; i <= m; i++) {
        is_prime[i] = true;
    }
    is_prime[0] = is_prime[1] = false;

    for (int i = 2; i <= (int)sqrt(m); i++) {
        if (is_prime[i]) {
            for (int j = i * i; j <= m; j += i) {
                is_prime[j] = false;
            }
        }
    }

    *prime_count = 0;
    for (int i = 2; i <= m; i++) {
        if (is_prime[i]) {
            (*prime_count)++;
        }
    }

    *primes = malloc((*prime_count) * sizeof(int));
    int index = 0;
    for (int i = 2; i <= m; i++) {
        if (is_prime[i]) {
            (*primes)[index++] = i;
        }
    }
    free(is_prime);
}

int max_(int m) {
    int *primes;
    int prime_count;
    Sieve(m, &primes, &prime_count);

    int budget = m;
    int stations = 0;
    for (int i = 0; i < prime_count; i++) {
        if (budget >= primes[i]) {
            budget -= primes[i];
            stations++;
        } else {
            break;
        }
    }
    free(primes);
    return stations;
}

int main() {
    int n, m;
    scanf("%d %d", &n, &m);
    int res = max_(m);
    printf("%d\n", res);
    return 0;
}