#include <iostream>
#include <fstream>

using namespace std;
string file = "transport";
ifstream fin( file + ".in" );
ofstream fout( file + ".out" );
int nrSaltele, nrTransporturi, capacitate, x;
int v[16005];
long long suma;
int reper, rez;
inline void impartire(){
    int val = v[1];
    int trans = 1;
    for( int i = 2; i <= nrSaltele; ++i ) {
        if(trans < nrTransporturi){
        if(val + v[i] > reper){
            val = v[i];
            trans++;
        }
        else
            val+=v[i];
        } else
            val+=v[i];
        rez = max(rez, val);

    }
}

int main(){
    fin>>nrSaltele>>nrTransporturi;
    for( int i = 1; i <= nrSaltele; ++i ){
        fin>>v[i];
        suma+=v[i];
    }
    double rez1 = (double)suma / nrTransporturi;
    int rez2 = suma / nrTransporturi;
    if( rez1 == rez2 )
        reper = rez2;
    else
        reper = rez2 + 1;
    impartire();
    fout<<rez;
    return 0;
}