#include<iostream>
#include<cstdio>
#define NUM 100010
#define ll long long
#define FOR(a,b,c) for( int a = b;a <= c;a++ )
using namespace std;

int n,m;
int a[NUM];
ll sum;
int big;

bool pan( ll ans ){
//    printf( "每組和最大為%d____________________________________\n",ans );
    int cnt = 0;//分成幾組
    ll now = 0;
    if( ans < big ) return 0; 
    FOR( i,1,n ){
        now += a[i];
        if( cnt > m ) return 0;
        if( i == n && now > ans ){
            cnt++;
//            printf( "%d",a[i] );
//            printf( " 大了，最后一段的值為%d,以上是第%d段\n",now,cnt );
            break;
        }
        if( i == n ){
//            printf( "%d",a[i] );
//            printf( "以上是第%d段\n",cnt );
            break;
        }
        if( now > ans ){
            cnt++;
            now = a[i];
//            printf( "以上是第%d段\n",cnt );
        }
//        printf( "%d ",a[i] );
    }

    if( cnt > m-1 ) return 0;
    return 1;
}

int main(){
    
    cin >> n >> m;
    FOR( i,1,n ){
        cin >> a[i];
        sum += a[i];
        big = max( big,a[i] );
    } 
    
    ll mid;
    ll l = 0,r = sum;
//    printf( "所有總和為%d\n",sum );
    while( l < r ){
        mid = ( l+r ) >> 1;
        if( pan(mid) ) r = mid;
        else l = mid+1;
    }
    
//    cout << endl << endl;
    cout << l;
    
    return 0;
}