#include <bits/stdc++.h>
using namespace std;
#ifndef LOCAL
#include "aliens.h"
#endif
long long take_photos(int n, int m, int k, vector<int> r, vector<int> c) {
using pii = pair<int, int>;
vector<pii> p(n);
bool sub2 = true;
for (int i = 0; i < n; ++i) {
if (r[i] > c[i]) swap(r[i], c[i]);
sub2 &= (r[i] == c[i]);
p[i] = {r[i], c[i]};
}
if (n <= 50 && m <= 100 && k == n) {
vector<vector<bool>> mk(m, vector<bool>(m));
for (int i = 0; i < n; ++i) {
auto [x, y] = p[i];
if (x > y) swap(x, y);
for (int i = x; i <= y; ++i) {
for (int j = x; j <= y; ++j) mk[i][j] = true;
}
}
int answer = 0;
for (int i = 0; i < m; ++i)
for (int j = 0; j < m; ++j) answer += mk[i][j];
return answer;
}
auto dis = [&](pii a) { return abs(a.first - a.second) + 1; };
sort(p.begin(), p.end());
p.resize(n = unique(p.begin(), p.end()) - p.begin());
k = min(k, n);
sort(p.begin(), p.end(), [&](const auto& a, const auto& b) {
return make_pair(a.first, dis(a)) < make_pair(b.first, dis(b));
});
vector<vector<long long>> f(k + 1, vector<long long>(n + 1, 1e15));
if (sub2) {
f[0][0] = 0;
for (int i = 1; i <= k; ++i) {
for (int j = 1; j <= n; ++j) {
auto& ret = f[i][j];
for (int t = 1; t <= j; ++t) {
int nval = (p[j - 1].first - p[t - 1].first + 1);
nval *= nval;
ret = min(ret, f[i - 1][t - 1] + nval);
}
}
}
return f[k][n];
}
return 0;
}
#ifdef LOCAL
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
int n, m, k; cin >> n >> m >> k;
vector<int> r(n), c(n);
for (int i = 0; i < n; ++i) cin >> r[i] >> c[i];
cout << take_photos(n, m, k, r, c) << "\n";
}
#endif
