#include<cstdio>

 #include<algorithm>

 #include<cstring>

 #define LL long long

 #define rg register

 #define N 200010

 using namespace std;

 int n,m,l,r,mid,a[N];

 inline int read(){

     int k=,f=; char c=getchar();

     while(c<''||c>'')c=='-'&&(f=-),c=getchar();

     while(''<=c&&c<='')k=k*+c-'',c=getchar();

     return k*f;

 }

 inline int max(int x,int y){return x>y?x:y;}

 inline bool check(){

     int sum=,cnt=;

     for(rg int i=;i<=n;i++){

         sum+=a[i];

         if(sum>mid) cnt++,sum=a[i];

     }

     return cnt<=m;

 }

 int main(){

     n=read(); m=read();

     for(rg int i=;i<=n;i++) a[i]=read(),l=max(l,a[i]-),r+=a[i];

     while(l+<r){

         mid=(l+r)>>;

         if(check()) r=mid; else l=mid;

     }

     printf("%d\n",r);

     return ;

 }