#include<bits/stdc++.h>
#define int long long
using namespace std;
int a[100010];
int n,m;
int l,r;
int mid; 
bool check(int x){
    if(a[1]>mid){
    	return 0;
	}
	int s=a[1],sum=1;
	for(int i=2;i<=n;i++){
		if(a[i]+s<=mid){
			s+=a[i];
		}
		else{
			s=a[i];
			sum++;
		}
	}
    return sum<=m;
}
signed main(){
    cin>>n>>m;
    int sum=0,maxx=-2e9;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        r+=a[i];
        l=max(a[i],maxx);
    }
    int cnt;
    while(l<=r){
        mid=(l+r)/2;
        if(check(mid)){
        	r=mid-1;
        	cnt=mid;
		}
        else{
        	l=mid+1;
		}
    }
    cout<<cnt;
    return 0;
}