#include <fstream>

using namespace std;

ifstream fin("transport.in");
ofstream fout("transport.out");

int v[16001];

int main()
{
    int n, k;
    fin>>n>>k;

    int maxi = -1, s = 0;
    for(int i=0; i<n ; i++){
       fin>>v[i];

       if(maxi < v[i])
        maxi = v[i];

       s = s + v[i];
    }
    int max1 = -1;
    int sol = -1, nr = 1;
    while(nr <= k){
        int so = 0;
        for(int i = 0; i < nr; i++)
            so = so + v[i];

        if(max1 < so)
         {
            max1 = so;
            sol = max1;
         }
        nr++;

   }

    fout<<sol;
    return 0;
}