#include<iostream>  
#include<cstdio>
#include<cmath>
#include<cctype>  
#include<cstring>  
#include<algorithm>  
using namespace std; 
long long n,m,a[100001],sum,ans;
int ju(long long x){
	long long p=0,ll=m;
	for(int i=1;i<=n;i++){
		if(a[i]>x)return 0;
		if((p+a[i])>x){
			p=a[i];
			ll-=1;
			if(ll<1)return 0;
		}
		else p+=a[i];
	}
	if(p!=0)ll-=1;
	if(ll<0)return 0;
	return 1;
}
int main(){ 
    freopen("expense.in","r",stdin);        
    freopen("expense.out","w",stdout);      
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		sum+=a[i];
	}
    long long l=1,r=sum;
	while(l<=r){
		long long mid=(l+r)/2;
		if(ju(mid)){
			ans=mid;
			r=mid-1;
		}
		else{
			l=mid+1;
		}
	}
	cout<<ans;
    return 0;  
}