int main()
{
size_t N;
scanf ("%zu", &N);
void* bitset = create_bitset (N + 1);
set_bitset (bitset, 0, 1);
set_bitset (bitset, 1, 1);
for (size_t i = 2; i*i <= N; ++i) {
if (!get_bitset (bitset, i)) {
for (size_t j = i*i; j <= N; j += i) {
set_bitset (bitset, j, 1);
}
}
}
size_t prime_count = 0;
for (size_t i = 0; i <= N; ++i) {
if (!get_bitset (bitset, i)) {
++prime_count;
}
}
destroy_bitset (bitset);
printf ("%zu\n", prime_count);
}
int main()
{
size_t infected, count;
scanf ("%zu %zu", &infected, &count);
void* bitset = create_bitset (count);
for (size_t i = 0; i < infected; ++i) {
size_t nr;
scanf ("%zu", &nr);
size_t delta = nr;
for (size_t j = nr; j < count; j += delta++) {
set_bitset (bitset, j, 1);
}
}
size_t infected_count = 0;
for (size_t i = 0; i < count; ++i) {
if (get_bitset (bitset, i)) {
++infected_count;
}
}
destroy_bitset (bitset);
printf ("%zu\n", infected_count);
}
int main(void)
{
int x, i, j;
scanf("%d", &x);
void* bitset = init_bitset(x + 1);
for(i = 2; i * i <= x; i++)
if(!get_bitset(bitset, i))
for(j = i * i; j <= x; j += i)
set_bitset(bitset, j, 1);
int count = 0;
for(i = 2; i <= x; i++)
if(!get_bitset(bitset, i))
count++;
printf("%d", count);
destroy_bitset(bitset);
return 0;
}
