#include<bits/stdc++.h> 
using namespace std;
typedef long long LL;
const int N=110000;
int n, m, a[N], b[N];
 
bool check(int x)
{
    int s=0, tm=1;
    for(int i=1;i<=n;i++)
    {
        s=s+b[i];
        if(s>=x)
        {
            tm++;if(tm>m)return 1;
            s=0;
        } 
    }
    return tm>m;
}
int main()
{
    scanf("%d%d", &n, &m);for(int i=1;i<=n;i++) scanf("%d", &a[i]);
    sort(a+1, a+n+1);
    int l=0, r=a[n]-a[1], ans=0;
    for(int i=2;i<=n;i++) b[i-1] = a[i] - a[i-1];
    n--;m--;
    while(l<=r)
    {
        LL mid=(l+r)/2;
        if(check(mid)) l=mid+1, ans=mid;    
        else          r=mid-1;
    }
    printf("%lld\n", ans);
    return 0;
}

#include<bits/stdc++.h> 
using namespace std;
typedef long long LL;
const int N=110000;
int n,m,a[N],b[N];
 
bool check(int x)
{
    int s=0,tm=1;
    for(int i=1;i<=n;i++)
    {
        s=s+b[i];
        if(s>=x)
        {
            tm++;if(tm>m)return 1;
            s=0;
        } 
    }
    return tm>m;
}
int main()
{
    scanf("%d%d",&n,&m);for(int i=1;i<=n;i++) scanf("%d",&a[i]);
    sort(a+1,a+n+1);
    int l=0,r=a[n]-a[1],ans=0;
	for(int i=2;i<=n;i++)b[i-1]=a[i]-a[i-1];
	n--;m--;
    while(l<=r)
    {
        LL mid=(l+r)/2;
        if(check(mid))l=mid+1,ans=mid;    
        else          r=mid-1;
    }
    printf("%lld\n",ans);
    return 0;
}