#include<bits/stdc++.h>
using namespace std;
long long n,m,a[1001000],l=0,r=0,mid,ans;
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++){
cin>>a[i];
l=max(l,a[i]);
r+=a[i];}
while(l<=r){
mid=(l+r)/2;
int sum=0,c=1;
for(int i=1;i<=n;i++){
if(sum+a[i]<=mid){
sum+=a[i];}
else {
sum=a[i];
c++;}}
if(c<=m){
r=mid-1;
ans=mid;}
else l=mid+1;}
cout<<ans;
return 0;}