#include <sstream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cassert>
#include <ctime>
#include <map>
#include <math.h>
#include <cstdio>
#include <set>
#include <deque>
#include <memory.h>
#include <queue>
#pragma comment(linker, "/STACK:64000000")
typedef long long ll;
using namespace std;
const ll INF = (ll)(1.1e12);
ll sqr(ll x) {
return x * x;
}
ll take_photos(int n, int m, int k, vector<int> x, vector<int> y) {
vector<pair<int, int> > a;
for (int i = 0; i < n; i++) {
a.push_back({ min(x[i], y[i]), max(x[i], y[i]) });
}
sort(a.begin(), a.end(), [](const pair<int, int> &a, const pair<int, int> &b) {
if (a.first != b.first) return a.first < b.first;
return a.second > b.second;
});
vector<pair<int, int> > aa;
for (int i = 0; i < (int)a.size(); i++) {
if (!aa.empty() && a[i].first >= aa.back().first && a[i].second <= aa.back().second) continue;
aa.push_back(a[i]);
}
a = aa;
n = a.size();
// dp[l][j - 1] + sqr(a[i - 1].second - a[l].first + 1) - sqr(max(0LL, (l ? a[l - 1].second : -INF) - a[l].first + 1))
ll ans = INF;
vector<ll> dp1, dp2;
dp1.assign(n + 1, INF);
dp1[0] = 0;
for (int j = 0; j < k; j++) {
dp2.assign(n + 1, INF);
vector<pair<pair<ll, ll>, int> > vct;
vct.push_back(make_pair(make_pair(0, INF), -1));
for (int i = 0; i <= n; i++) {
if (i) {
int l = -1, r = vct.size();
while (r - l > 1) {
int m = (l + r) >> 1;
if (m == 0) {
l = m;
continue;
}
ll c1 = vct[m - 1].first.first, b1 = vct[m - 1].first.second;
ll c2 = vct[m].first.first, b2 = vct[m].first.second;
if (c1 * a[i - 1].second + b1 >= c2 * a[i - 1].second + b2) l = m;
else r = m;
}
dp2[i] = sqr(a[i - 1].second) + vct[l].first.first * (a[i - 1].second) + vct[l].first.second;
}
if (i < n && dp1[i] < INF) {
// cx + b
ll b3 = -sqr(max(0LL, (i ? a[i - 1].second : -INF) - a[i].first + 1)) + sqr(a[i].first - 1) + dp1[i];
ll c3 = 2 * (-a[i].first + 1);
while (vct.size() > 1) {
ll c1 = vct[(int)vct.size() - 2].first.first, b1 = vct[(int)vct.size() - 2].first.second;
ll c2 = vct.back().first.first, b2 = vct.back().first.second;
if (c3 * (b2 - b1) + b3 * (c1 - c2) <= c2 * (b2 - b1) + b2 * (c1 - c2)) {
vct.pop_back();
}
else {
break;
}
}
vct.push_back(make_pair(make_pair(c3, b3), i));
}
}
ans = min(ans, dp2[n]);
swap(dp1, dp2);
}
return ans;
}
// BEGIN CUT
/*
int main() {
#ifdef _MSC_VER
freopen("input.txt", "r", stdin);
#endif
int n, m, k;
scanf("%d%d%d", &n, &m, &k);
vector<int> x(n), y(n);
for (int i = 0; i < n; i++) cin >> x[i] >> y[i];
ll ans = take_photos(n, m, k, x, y);
// BEGIN SECRET
puts("098d134608c94f7413faac591054ee35");
// END SECRET
cout << ans << endl;
return 0;
}
*/
// END CUT
