#include #include #include #include #include #include #include #define REP(i, a, b) for (int i = int(a); i < int(b); i++) using namespace std; using ll = long long int; using P = pair; // clang-format off #ifdef _DEBUG_ #define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false) template void PPPPP(T t) { cerr << t; } template void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); } #else #define dump(...) do{ } while(false) #endif template vector make_v(size_t a, T b) { return vector(a, b); } template auto make_v(size_t a, Ts... ts) { return vector(a, make_v(ts...)); } template bool chmin(T &a, T b) { if (a > b) {a = b; return true; } return false; } template bool chmax(T &a, T b) { if (a < b) {a = b; return true; } return false; } template void print(T a) { cout << a << endl; } template void print(T a, Ts... ts) { cout << a << ' '; print(ts...); } template istream &operator,(istream &in, T &t) { return in >> t; } // clang-format on class UnionFind { public: vector par; int N; UnionFind(int n) { par.resize(n, -1); N = n; } int Find(int n) { return par[n] < 0 ? n : par[n] = Find(par[n]); } bool Union(int x, int y) { x = Find(x); y = Find(y); if (x == y) return false; if (-par[x] > -par[y]) swap(x, y); par[y] += par[x]; par[x] = y; N--; return true; } bool Same(int x, int y) { return Find(x) == Find(y); } int size(int x) { return -par[Find(x)]; } int size() { return N; } }; int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n, p; cin, n, p; UnionFind uf(n); for (int i = 2; i <= n; i++) { for (int j = 2 * i; j <= n; j += i) { uf.Union(i - 1, j - 1); } } cout << uf.size(p - 1) << endl; return 0; }