#pragma GCC target("avx2") #pragma GCC optimize("unroll-loops") #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define ALL(x) (x).begin(), (x).end() #define PC(x) __builtin_popcount(x) #define PCL(x) __builtin_popcountll(x) using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair pii; typedef pair pll; struct edge { int to, cost, id; }; const double PI = 3.14159265358979323846; const double PI2 = PI * 2.0; const double EPS = 1E-09; const ll MOD = 1E+09 + 7; // =998244353; const ll INFL = 1E18; const int INFI = 1E09; const int MAX_N = 2E+05; ll dx[4] = { 0, -1, 0, 1 }, dy[4] = { 1, 0, -1, 0 }; int N, M; int A[MAX_N + 1]; bool sabo[MAX_N + 1], open[MAX_N + 1]; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); cin >> N >> M; for (int i = 1; i <= M; ++i) { cin >> A[i]; open[A[i]] = true; } int ans = 0; for (int i = N; i >= 1; --i) { bool flg = false; for (int j = 2 * i; j <= N; j += i) { if (sabo[j]) continue; flg = !flg; } if (flg == open[i]) { sabo[i] = true; ans++; } } // for (int i = 0; i < N; i++) { // for (int j = 0; j < N; j++) { // cout << "i = " << i << ", j = " << j << ", dp = " << dp[i][j] << "\n"; // } // } cout << ans << "\n"; return 0; }