#include <bits/stdc++.h>
#ifndef SKY
#include "aliens.h"
#endif // SKY
using namespace std;
#define ll long long
#define pb push_back
#define N 100010
#define ii pair<int,int>
#define fs first
#define sc second
ll l[N],r[N],dp[510][510];
ii a[N];
bool SS(const ii&u,const ii&v)
{
if(u.fs!=v.fs)
return u<v;
return(u.sc>v.sc);
}
ll sqr(ll x)
{
return x*x;
}
void selfmin(ll&u,ll v)
{
u=min(u,v);
}
ll take_photos(int n, int m, int k, vector<int> r, vector<int> c)
{
for(int i=0;i<n;i++)
{
a[i+1].fs=min(r[i],c[i])+1;
a[i+1].sc=max(r[i],c[i])+1;
}
sort(a+1,a+1+n,SS);
int dem=0,max_r=0;
for(int i=1;i<=n;i++)
{
if(a[i].sc<=max_r)
continue;
max_r=a[i].sc;
l[++dem]=a[i].fs;
r[dem]=a[i].sc;
}
n=dem;
k=min(k,n);
// for(int i=1;i<=n;i++)cout<<l[i]<<" "<<r[i]<<endl;
memset(dp,0x3f3f,sizeof(dp));
for(int i=1;i<=n;i++)
dp[i][1]=sqr(l[i]-l[1]+1);
for(int t=1;t<=k;t++)
for(int i=t;i<=n;i++)
for(int j=t;j<=i;j++)
selfmin(dp[i][t],dp[j-1][t-1]+sqr(l[i]-l[j]+1));
return dp[n][k];
}
#ifdef SKY
int main()
{
freopen("A.inp","r",stdin);
freopen("A.out","w",stdout);
int n,m,k;
vector<int>r,c;
cin>>n>>m>>k;
for(int i=1;i<=n;i++)
{
int u,v;
cin>>u>>v;
r.pb(u);
c.pb(v);
}
cout<<take_photos(n,m,k,r,c);
}
#endif
