# include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
using namespace std;
const int N=2005;
long long le,ri,mid,n,a[N],m,pr[N],pr1[N],dp[N][N],w,k,ans;
int check(int mid) {
for (int i=0; i<=n; i++) {
for (int j=0; j<=n; j++) {
dp[i][j]=1e9;
}
}
dp[0][0]=0;
w=mid;
for (int i=1; i<=n; i++) {
pr[i]=pr1[i]=0;
for (int j=i; j>=1; j--) {
if (a[i]-a[j]>=w && !pr[i]) {
pr[i]=j;
// break;
}
if (a[i]-a[j]>=2*w && !pr1[i]) {
pr1[i]=j;
// break;
}
}
// cout<<i<<" "<<pr[i]<<" "<<pr1[i]<<endl;
}
for (int i=1; i<=n; i++) {
for (int j=0; j<=min(m,(long long)i); j++) {
if(j)
dp[i][j]=dp[pr[i]][j-1];
dp[i][j]=min(dp[i][j],dp[pr1[i]][j]+1);
if (i==n && dp[n][j]<=k) return 1;
}
}
//if (dp[n][m]<=k) return 1;
return 0;
}
int main() {
cin>>n>>m>>k;
for (int i=1; i<=n; i++) {
cin>>a[i];
}
sort(a+1, a+n+1);
for (int i=1; i<=n; i++) {
for (int j=i; j>=1; j--) {
if (a[i]-a[j]>w) {
pr[i]=j;
break;
}
if (a[i]-a[j]>2*w) {
pr1[i]=j;
break;
}
}
}
le=1;
ri=1e9;
while (le<=ri) {
mid=(le+ri)/2;
if (check(mid)) {
ri=mid-1;
ans=mid;
}
else {
le=mid+1;
}
}
cout<<ans<<endl;
}
