#include<fstream.h>
int n,k,max,x;
double s;
int main()
{int i;
ifstream f("transport.in");
f>>n>>k;
for(i=1;i<n+1;i++)
{f>>x;s=s+x;
if(x>max)
max=x;}
f.close();

ofstream g("transport.out");
s=s/k;

if(long(s)==max||long(s)<max) g<<max;
else {if(s!=(long)s) s=long(s)+1;
else s=long(s);g<<s+2;}


return 0;}