#include <fstream>
using namespace std;
ifstream fin("grupuri.in");
ofstream fout("grupuri.out");
int w[100005];
int main()
{
    int k, n, a, ii=0;
    fin >> k >> n;
    for(int i=1; i<=n; i++)
    {
        fin >> a;
        int st=0, dr=ii+1, mid;
        while(st<dr-1)
        {
            mid=(st+dr)/2;
            if(a+w[mid]<=n)
                st=mid;
            else
                dr=mid;
        }
        if(st)
            w[st]+=a;
        else
        {
            ii++;
            w[ii] = a;
        }
    }
    fout << ii;
    return 0;
}