#include <fstream>

using namespace std;

ifstream fin ("light2.in");
ofstream fout ("light2.out");

typedef long long int64;

int64 N; int M; int64 V[25];int64 Response;


void Read() {

    fin >> N >> M;
    for(int i = 1; i <= M; ++i)
        fin >> V[i];
}


inline int64 GCD(int64 A, int64 B) {
    int64 R;
    while(B) {R = A % B; A = B; B = R;}

    return A;
}


inline void Back(int pos, int64 Value, int64 op, int64 P) {
    int64 T;
    for(int i = pos + 1; i <= M; ++i) {
        T = Value * V[i] / GCD(V[i], Value);
        Response += (N / T) * op * P;
        Back(i, T, -op, P * 2);
    }
}


void Print() {

    fout << Response <<'\n';
}


int main() {

    Read ();

    for(int i = 1; i <= M; ++i){
        Response += N / V[i];
        Back(i , V[i], -1, 2);
    }

    Print ();

    return 0;
}