import java.util.*;
import java.io.*;
public class Main {
    static class Scan {
        private byte[] buf=new byte[1024];
        private int index;
        private InputStream in;
        private int total;
        public Scan()
        {
            in=System.in;
        }
        public int scan()throws IOException
        {
            if(total<0)
            throw new InputMismatchException();
            if(index>=total)
            {
                index=0;
                total=in.read(buf);
                if(total<=0)
                return -1;
            }
            return buf[index++];
        }
        public int scanInt()throws IOException
        {
            int integer=0;
            int n=scan();
            while(isWhiteSpace(n))
            n=scan();
            int neg=1;
            if(n=='-')
            {
                neg=-1;
                n=scan();
            }
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    integer*=10;
                    integer+=n-'0';
                    n=scan();
                }
                else throw new InputMismatchException();
            }
            return neg*integer;
        }
        public double scanDouble()throws IOException
        {
            double doub=0;
            int n=scan();
            while(isWhiteSpace(n))
            n=scan();
            int neg=1;
            if(n=='-')
            {
                neg=-1;
                n=scan();
            }
            while(!isWhiteSpace(n)&&n!='.')
            {
                if(n>='0'&&n<='9')
                {
                    doub*=10;
                    doub+=n-'0';
                    n=scan();
                }
                else throw new InputMismatchException();
            }
            if(n=='.')
            {
                n=scan();
                double temp=1;
                while(!isWhiteSpace(n))
                {
                    if(n>='0'&&n<='9')
                    {
                        temp/=10;
                        doub+=(n-'0')*temp;
                        n=scan();
                    }
                    else throw new InputMismatchException();
                }
            }
            return doub*neg;
        }
        public String scanString()throws IOException
        {
            StringBuilder sb=new StringBuilder();
            int n=scan();
            while(isWhiteSpace(n))
            n=scan();
            while(!isWhiteSpace(n))
            {
                sb.append((char)n);
                n=scan();
            }
            return sb.toString();
        }
        private boolean isWhiteSpace(int n)
        {
            if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
            return true;
            return false;
        }
    }
    static int n,k;
    static long a[];
    public static void main(String args[]) throws IOException {
        Scan input=new Scan();
        n=input.scanInt()+1;
        k=input.scanInt();
        a=new long[500000];
        a[1]=1;
        for(int i=2;i<=n;i++) {
            a[i]=a[i-1]+input.scanInt();
        }
        int ans = binsearch(1, (int)Math.pow(10, 9));
        System.out.println(ans);
    }
    
    static boolean check(int x) {
	int reqd = 0;
	for(int i = 1; i + 1 <= n; i++)
	{
		long diff = a[i + 1] - a[i];
		reqd += (diff - 1) / x;
		if(reqd > k)
			return false;
	}
	return true;
    }

    static int binsearch(int lo, int hi) {
        while(lo < hi)
        {
            int mid = (lo + hi) / 2;
            if(check(mid))
                    hi = mid;
            else
                    lo = mid + 1;
        }
        return lo;
    }
}


Measured memory_bytes: 37332