#include<bits/stdc++.h>
#define STIZE(x) fprintf(stderr, "STIZE%d\n", x);
#define PRINT(x) fprintf(stderr, "%s = %d\n", #x, x);
#define NL(x) printf("%c", " \n"[(x)]);
#define lld long long
#define pii pair<int,int>
#define pb push_back
#define fi first
#define se second
#define all(a) begin(a),end(a)
#define sz(a) int((a).size())
#define LINF 1000000000000000
#define INF 1000000000
#define EPS 1e-9
using namespace std;
#define MAXK 23
lld N, K;
lld d[MAXK];
lld popcnt(lld x) {
    lld rez = 0;
    while(x) {
        x -= x&-x;
        rez++;
    }
    return rez;
}
lld koliko(lld mask) {
    lld gcd = 0;
    for(lld i = 0; i < K; i++) {
        if((1<<i)&mask) {
            if(gcd == 0) gcd = d[i];
            else gcd = __gcd(d[i], gcd);
        }
    }
    lld lcm = gcd;
    for(lld i = 0; i < K; i++) {
        if((1<<i)&mask) {
            lcm *= (d[i]/gcd);
            if(lcm > N || lcm <= 0) return 0;
        }
    }
    return N/lcm;
}

int main() {
    //freopen("light2.in", "r", stdin);
    //freopen("light2.out", "w", stdout);
    scanf("%lld%lld", &N, &K);
    for(lld i = 0; i < K; i++) {
        scanf("%lld", &d[i]);
    }
    lld parn = 0, nepar = 0;
    for(lld i = 1; i < (1<<K); i++) {
        lld bitova = popcnt(i);
        if(bitova&1) nepar += (1LL << (bitova-1)) * koliko(i);
        else parn += (1LL << (bitova-1)) * koliko(i);
        //printf("%lld\n", rez);
    }
    printf("%lld", parn-nepar);
    return 0;
}