#include<bits/stdc++.h>
using namespace std;

long long m,n,t[25];

bool check(long long x)
{
    int S=0;
    for(int i=1;i<=n;i++)
    {
        S+=x/t[i];
    }
//  cout<<x<<" "<<S<<endl;
    if(S>=m)
    {
        return true;
    }
    return false;
}

main()
{
 freopen("pancake.inp","r",stdin);
freopen("pancake.out","w",stdout);
    cin>>m>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>t[i];
    }

    long long dau=0,cuoi=t[1]*n;
    long long giua=(dau+cuoi)/2;
    long long ans;
    while(dau<=cuoi)
    {
        int giua=(dau+cuoi)/2;
        if(check(giua)==true)
        {
            ans=giua;
            cuoi=giua-1;
        }
        else
        {
            dau=giua+1;
        }
    }
    cout<<ans;
}