#ifdef LOCAL111 #else #define NDEBUG #endif #include const int INF = 1e8; using namespace std; #define endl '\n' #define ALL(a) (a).begin(),(a).end() #define SZ(a) int((a).size()) #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--) #define REP(i,n) FOR(i,0,n) #define RREP(i,n) for (int i=(n)-1;i>=0;i--) #define RBP(i,a) for(auto& i : a) #ifdef LOCAL111 #define DEBUG(x) cout<<#x<<": "<<(x)< void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;} template bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;} template bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;} typedef pair P; typedef long long int LL; typedef unsigned long long ULL; typedef pair LP; void ios_init(){ //cout.setf(ios::fixed); //cout.precision(12); #ifdef LOCAL111 return; #endif ios::sync_with_stdio(false); cin.tie(0); } std::vector eratosthenes(int n){ std::vector res(n+1,true); res[0] = false; res[1] = false; for(int i = 2; i*i <= n; i++){ for(int j = 2; i*j <= n; j++){ res[i*j] = false; } } return res; } int main() { ios_init(); int m,n; cin >> m >> n; vector c(n); REP(i,n) cin >> c[i]; auto sosu = eratosthenes(m+1); vector dp(m+1,-INF); dp[m] = 0; REP(i,n){ RREP(j,m+1-c[i]){ dp[j] = max(dp[j+c[i]]+1,dp[j]); } } int ans = 0; REP(i,m){ if(sosu[i] and dp[i] >= 0) ans += dp[i]; } /*REP(i,SZ(dp)) if(dp[i] >= 0){ DEBUG(i); DEBUG(dp[i]); }*/ ans += *max_element(ALL(dp)); cout << ans << endl; return 0; }