#include<bits/stdc++.h>

using namespace std;
typedef long long int ll;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define BIGINT 0x7FFFFFFF

template<typename T1,typename T2>
ostream& operator <<(ostream &o,const pair<T1,T2> p){o<<"("<<p.first<<":"<<p.second<<")";return o;}

bool nprime[10005];

void makefurui(){
    int i,j;
    nprime[0]=true;
    nprime[1]=true;
    for (i=2;i*i<10005;i++){
        if (nprime[i]) continue;
        for (j=i*2;j<10005;j+=i){
            nprime[j]=true;
        }
    }
}

int dp[10005];

int main(){
    int i,j,k,l;
    int m,n;
    
    makefurui();
    
    cin >> m>>n;
    
    vector<int> men(n);
    
    for (i=0;i<n;i++){
        scanf("%d",&men[i]);	
    }
    
    dp[m]=1;
    for (i=m;0<i;i--){
        if (dp[i]==0) continue;
        for (int e:men){
            if (i-e>=0 && dp[i-e]<dp[i]+1){
                dp[i-e]=dp[i]+1;
            }
        }
    }
    
    int sp=0,min=-1;
    for (i=0;i<=m;i++){
        if (dp[i]>0){
            if (min==-1) min=i;
            if (!nprime[i]){sp+=dp[i]-1;}
        }
    }
    
    if (min==-1){
        cout << 0 << endl;
        return 0;
    }
    if (sp==-1){
        cout<<dp[min]<<endl;
        return 0;
    }
    cout<<(sp+dp[min]-nprime[m])<<endl;
    
    return 0;
}