#include<fstream.h>
int max,i,n,k,a[16000],y,s,v;
ifstream f("transport.in");
ofstream g("transport.out");
int main(){
f>>n>>k;
max=0;
for(i=1;i<=n;i++){
    f>>a[i];
    if(a[i]>max)
      max=a[i];
    s=s+a[i];}
if(s/k+s%k>max)
  max=s/k+s%k;
s=0;
for(i=1;i<=n;i++){
    s=s+a[i];
    if(s>max){
      v=s-a[i];
      s=a[i];}}
g<<v;

f.close();
g.close();
return 0;}