#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,m,a[25],b[25],ans=1e18;
signed main()
{
	//freopen("tree.in","r",stdin);
	//freopen("tree.out","w",stdout);
    cin.tie(0)->sync_with_stdio(0);
    cin>>n>>m;
	for(int i=0;i<n;i++)cin>>a[i];
	for(int i=0;i<(1<<n);i++)
	{
		if(__builtin_popcount(i)!=m||i%2==0)continue;
		for(int j=0;j<n;j++)b[j]=a[j];
		int lst=-1,val=0;
		for(int j=0;j<n;j++)
		{
			if(i&(1<<j))
			{
				if(lst!=-1&&b[j]<=b[lst])val+=b[lst]-b[j]+1,b[j]=b[lst]+1;
				lst=j;
			}
			else 
			{
				if(lst!=-1&&b[j]>b[lst])val+=b[j]-b[lst],b[lst]=b[j];
			}
		}
		ans=min(ans,val);
	}
	cout<<ans;
	return 0;
}