#include <iostream>
#include <fstream>


using namespace std;
ifstream in("transport.in");
ofstream out("transport.out");





int main()
{
int n,k,i,c,ctemp,ktemp,v[16001];
in>>n>>k;
for(i=0;i<n;i++)
	in>>v[i];
for(c=1;c<256000000;c++)
{ctemp=c;ktemp=k;
for(i=0;i<n;i++)
	{if(v[i]<=ctemp)ctemp-=v[i];
		else {ktemp--;ctemp=c;i--; if(!ktemp)break;    }
	}



if((ktemp>0||(ktemp==0&&i==n)))	{out<<c;return 0;}

	
	
	
}
return -1;
  
}