#include <fstream>
#include <algorithm>
using namespace std;
int a[1000001];
long long b[1000001];
int main()
{ int n,k,i,j,x;
long long nr=0;
    ifstream f("grupuri.in");
    ofstream g("grupuri.out");
    f>>k>>n;
    for (i=1;i<=n;++i)
      f>>a[i];
      sort(a+1,a+n+1);
    while (a[n-k+1]>0) {
        long long sum=0;
       x=a[n-k+1];
       nr+=x;
       for (i=1;i<=n;++i) {
         sum+=b[i-1];
         if (i==1) b[i]=a[i];
         else b[i]=a[i]-sum;
       }
       b[n-k+1]-=x;
       b[n+1]+=x;
       sum=0;
       for (i=1;i<=n;++i) {
          sum+=b[i];
          a[i]=sum;
       }
       sort(a+1,a+n+1);
    }
      g<<nr;
    return 0;
}