#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <stack>
#include <queue>
#include <bitset>
#include <numeric>
#include <cassert>
#include <array>
#include <memory>
#include <random>
#include <functional>
#include <complex>
#ifdef DEBUG
#include "./Lib/debug.hpp"
#include "./Lib/Timer.hpp"
#include "./Lib/sample.hpp"
#else
#define dump(...)
#endif

/* (=＾o＾=) */
//#define int ll

/* macro */
#define FOR(i, b, e) for(ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for(ll i = (ll)(e-1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x,c) for(const auto& x:(c))
#define REPI2(it,b,e) for(auto it = (b); it != (e); ++it)
#define REPI(it,c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it,c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for(auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(),(x).end()
#define cauto const auto&
/* macro func */
template<class T>
inline void sort(T& t) { std::sort(ALL(t)); }
template<class T>
inline void rsort(T& t) { std::sort((t).rbegin(), (t).rend()); }
template<class T>
inline void unique(T& t) { (t).erase(unique((t).begin(), (t).end()), (t).end()); }
template<class T, class S>
inline bool chmax(T& t, const S& s) { if (s > t) { t = s; return true; } return false; }
template<class T, class S>
inline bool chmaxE(T& t, const S& s) { if (s >= t) { t = s; return true; } return false; }
template<class T, class S>
inline bool chmin(T& t, const S& s) { if (s < t) { t = s; return true; } return false; }
inline void BR() { std::cout << "\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template<class T>
using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\n';
using std::cin;
using std::pair;
using std::string;
using std::stack;
using std::queue;
using std::vector;
using std::list;
using std::map;
using std::unordered_map;
using std::multimap;
using std::unordered_multimap;
using std::set;
using std::unordered_set;
using std::unordered_multiset;
using std::multiset;
using std::bitset;
using std::priority_queue;
using std::tuple;

/* constant value */
constexpr ll MOD = 1000000007;
//constexpr ll MOD = 998244353;
//constexpr ll MOD = 2;

/* Initial processing  */
struct Preprocessing { Preprocessing() { std::cin.tie(0); std::ios::sync_with_stdio(0); }; }_Preprocessing;

/* Remove the source of the bug */
inline signed pow(signed, signed) { assert(false); return -1; }

/* define hash */
namespace std {
template <>	class hash<std::pair<ll, ll>> { public:	size_t operator()(const std::pair<ll, ll>& x) const { return hash<ll>()(1000000000 * x.first + x.second); } };
}

/* input */
template<class T> std::istream& operator >> (std::istream& is, vector<T>& vec) { for (T& x : vec) is >> x; return is; }

//=============================================================================================

auto solve(ll n, ll k, const V<PAIR>& ba) {

	priority_queue<PAIR> q;
	REP(_, n) {
		q.emplace(ba[_].first, ba[_].second);
	}

	set<ll> var;
	priority_queue<ll> q2;
	multiset<ll> lst;
	while (!q.empty()) {
		auto p = q.top();
		q.pop();
		if (var.find(p.second) != var.end()) {
			q2.emplace(p.first);
			continue;
		}
		if (var.size() == k) {
			q2.emplace(p.first);
			continue;
		}
		var.emplace(p.second);
		lst.emplace(p.first);
	}

	if (var.size() < k) {
		ll t = var.size();
		REP(_, k - t) { lst.emplace(q2.top()); q2.pop(); }
		k = t;
	}

	ll ans = 0;
	ll ad = 0;
	{
		ll now = k * k;
		REPC(x, lst) { ad += x; }
		now += ad;
		chmax(ans, now);
	}

	ll i = 1;
	while (!q2.empty() && !lst.empty()) {
		ll val = q2.top();
		q2.pop();
		if (val < *lst.begin()) { break; }
		ad -= *lst.begin();
		ad += val;
		lst.erase(lst.begin());
		ll now = (k - i) * (k - i) + ad;
		chmax(ans, now);
		++i;
	}
	return ans;
}

auto solve_c(ll n, ll k, const V<PAIR>& ba) {
	ll ans = 0;
	REP(i, (1LL << n)) {
		ll val = 0;
		ll cnt = 0;
		unordered_set<ll> s;
		REP(j, n)if ((i >> j) & 1) {
			s.emplace(ba[j].second);
			val += ba[j].first;
			++cnt;
		}
		if (cnt != k) { continue; }
		ll t = s.size();
		chmax(ans, t * t + val);
	}
	return ans;
}

auto solve2(ll n, ll k, V<PAIR>& ba) {

	std::sort(ALL(ba), [](cauto a, cauto b) {
		if (a.first == b.first) {
			return a.second > b.second;
		}
		return a.first > b.first;
	});

	ll now = 0;
	list<ll> old;
	unordered_set<ll> var;
	REP(i, k) {
		now += ba[i].first;
		if (var.find(ba[i].second) == var.end()) {
			var.emplace(ba[i].second);
		} else {
			old.emplace_back(ba[i].first);
		}
	}
	ll t = var.size();
	ll ans = now + t * t;
	FOR(i, k, n) {
		if (old.empty()) { break; }
		if (var.find(ba[i].second) != var.end()) { continue; }
		now -= *old.rbegin();
		old.pop_back();
		now += ba[i].first;
		var.emplace(ba[i].second);
		ll t = var.size();
		chmax(ans, now + t * t);
	}
	return ans;

}
signed main() {
	/**/
	ll n, k;
	cin >> n >> k;
	V<PAIR> ba; ba.reserve(n);
	REP(_, n) {
		ll a, b;
		cin >> a >> b;
		ba.emplace_back(b, a);
	}

	auto ans = solve2(n, k, ba);
	cout << ans << endl;
	/*/
	auto gen = Sample::SampleGenerator();
	REP(_, 100) {
		auto [n] = gen.generate(PAIR{3,15});
		auto [k] = gen.generate(PAIR{1,n});
		auto [a, b] = gen.generate(V<PAIR>(n, PAIR{1,5}), V<PAIR>(n, PAIR{1,10}));
		V<PAIR> ba; ba.reserve(n);
		REP(i, n) { ba.emplace_back(b[i], a[i]); }

		auto ans = solve(n, k, ba);
		auto ans_c = solve_c(n, k, ba);
		if (ans != ans_c) {
			cout << n << " " << k << endl;
			REPC(x, ba) {
				cout << x.second << " " << x.first << endl;
			}

			dump(ans, ans_c);
			return 0;
		}
	}
	cout << "fin" << endl;
	/**/

}



Measured memory_bytes: 6284