#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
const int nax=50005;
vector<pair<int,int>> v;
long long dp[nax][105];
bool compare(pair<int,int> a,pair<int,int> b){
if(a.fi!=b.fi) return a.fi<b.fi;
return a.se>b.se;
}
void daq(int l,int r,int left,int right,int level){
if(l>r) return;
int mid=(r+l)/2;
if(dp[mid][level]<1e18) return;
int opt=0;
int lst=v[mid].se;
int cur=1;
//cout <<l<<" "<<r<<" "<<left<<" "<<right<<" "<<mid<<endl;
for (int i = min(right,mid); i >= left; --i)
{
if(i==0){
dp[mid][level]=cur*cur;
continue;
}
cur+=lst-v[i].fi;
lst=v[i].fi;
long long nabba=dp[i-1][level-1]+cur*cur-max(0,v[i-1].se-v[i].fi+1)*max(0,v[i-1].se-v[i].fi+1);
if(dp[mid][level]>nabba){
opt=i;
dp[mid][level]=nabba;
}
//cout <<mid<<" "<<i<<" "<<nabba<<" "<<dp[i-1][level-1]<<" "<<level<<endl;
}
//cout <<dp[mid][level]<<" "<<opt<<endl;
if(l==r) return;
daq(l,mid,left,opt,level);
daq(mid+1,r,opt,right,level);
}
long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c){
pair<int,int> tab[n];
for (int i = 0; i < n; ++i)
{
tab[i]={min(r[i],c[i]),max(r[i],c[i])};
}
sort(tab,tab+n,compare);
v.push_back({-1,-1});
for (int i = 0; i < n; ++i)
{
if(v.empty()) v.push_back(tab[i]);
else if(v.back().se>=tab[i].se) continue;
else v.push_back(tab[i]);
}
n=v.size();
long long cur=1;
long long lst=v[1].fi;
for (int i = 0; i < n; ++i)
{
if(i>0){
cur+=v[i].se-lst;
//cout<<lst<<" "<<cur<<endl;
lst=v[i].se;
dp[i][1]=cur*cur;
}
for (int j = 0; j <= k; ++j)
{
if(j>1) dp[i][j]=1e18;
else if(!j) dp[i][j]=0;
}
}
for (int i = 2; i <= min(k,n-1); ++i)
{
daq(1,n-1,0,n-1,i);
}
long long ans=m*m;
for (int i = 1; i <= min(k,n-1); ++i)
{
ans=min(ans,dp[n-1][i]);
}
return ans;
}
/*int main() {
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
int n, m, k;
assert(3 == scanf("%d %d %d", &n, &m, &k));
std::vector<int> r(n), c(n);
for (int i = 0; i < n; i++) {
assert(2 == scanf("%d %d", &r[i], &c[i]));
}
long long ans = take_photos(n, m, k, r, c);
printf("%lld\n", ans);
return 0;
}*/
