#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>

/***** type *****/
using namespace std;
using ll = long long;
using ld = long double;
template <class T> using vt = vector<T>;
template <class T> using vvt = vector<vector<T>>;
template <class T> using vvvt = vector<vector<vector<T>>>;
using ml = boost::multiprecision::cpp_int;

/***** define *****/
#define all(c) (c).begin(), (c).end()            // begin to end
#define rep(i, b, e) for (ll i = b; i < e; i++)  // repeat
#define repr(i, b, e) for (ll i = b; e < i; i--) // repeat reverse
#define val(itr) *(itr)                          // get value
/***** const value *****/
#define llong_max 9223372036854775807            // 9 * 10^18
#define ldbl_max 1.79769e+308                    // 1.7 * 10^308
#define mod 1000000007                           // 1e9 + 7
#define pi 3.14159265                            // 3.14 ...
/***** for each macro *****/
#define fori(i, ...) if(ll i = -1) for(__VA_ARGS__) if(i++, true)
#define each(i, e, c) fori(i, auto e = c.begin(); e != c.end(); ++e)
#define forir(i, v, ...) if(ll i = Size(v)) for(__VA_ARGS__) if(i--, true)
#define eachr(i, e, c) forir(i, auto e = c.rbegin(); e != c.rend(); ++e)

/***** lambda *****/
auto Count = [] // long long count value
(auto b, auto e, auto x) { return (ll)count(b, e, x); };
auto CtoN = [] // char to number
(auto c) { return (ll)(c - '0'); };
auto DivC = [] // long double div ceiling
(auto a, auto b) { return ceil((ld)a / (ld)b); };
auto Fix = [] // fix value
(auto b, auto e, auto fix)
{ for (auto it = b; it != e; ++it)* it += fix; }; 
auto NyaN = [] // long long nyan size
(auto n) { return (ll)pow(10, n); };
auto Pow = [] // long long pow
(auto a, auto b) { return (ll)pow(a, b); };
auto Pow2 = [] // long long pow2
(auto n) { return (1LL << n); };
auto Size = []  // long long collection size
(auto& c) { return (ll)(c).size(); };
auto Sum = [] // long long accumulate
(auto b, auto e) { return accumulate(b, e, 0LL); };

/***** template *****/
template <class T> vvt<T> VVT
(ll ys, ll xs, T fill = T())
{	// vector<vector<T>> resize + fill
	vvt<T> v(ys);
	each(i, y, v) { val(y).resize(xs, fill); } return v;
}
template <class T> vvvt<T> VVVT
(ll zs, ll ys, ll xs, T fill = T())
{	// vector<vector<vector<T>>> resize + fill
	vvvt<T> v(zs);
	each(i, z, v) { val(z) = VVT(ys, xs, fill); } return v;
}
template <class T> vt<T> InputVT
(ll size, T fix = T())
{   // input vector<T> (T != struct) + fix
	vt<T> v(size);
	each(i, e, v) { cin >> val(e); val(e) += fix; } return v;
}
template <class T> vvt<T> InputVVT
(ll ys, ll xs, T fix = T())
{   // input vector<vector<T>> (T != struct) + fix
	vvt<T> v(ys); each(i, y, v) val(y).resize(xs);
	each(i, y, v) each(j, x, val(y)) { cin >> val(x); val(x) += fix; } return v;
}
template <class T> vvvt<T> InputVVVT
(ll zs, ll ys, ll xs, T fix = T())
{	// input vector<vector<vector<T>>> (T != struct) + fix
	vvvt<T> v(zs);
	each(i, z, v) { val(z) = InputVVT<T>(ys, xs, fix); } return v;
}

struct Score
{
	ll base = 0;
	map<ll, ll> type;
	ll Result(void)
	{
		return base + Size(type) * Size(type);
	}
};

struct Sushi
{
	ll d;
	ll t;
};

auto NyaSort = [](const Sushi& l, const Sushi& r)
{	// 降順は演算子>, 昇順は演算子<, if順の優先でソートされる
	return l.d > r.d;
};

bool operator < (const Sushi& l, const Sushi& r)
{	// 
	return l.d > r.d;
};

int main(void)
{
	ll N, K; cin >> N >> K;
	vt<Sushi> sushi(N);
	rep(i, 0, N) cin >> sushi[i].t >> sushi[i].d;
	sort(all(sushi), NyaSort);

	Score score;
	vt<priority_queue<Sushi>> test(NyaN(5)+1);
	rep(i, 0, K) test[sushi[i].t].push(sushi[i]);

	priority_queue<Sushi> sushiPQ;
	each(i, t, test)
	{
		while (Size(val(t)) != 0)
		{
			if (Size(val(t)) == 1)
			{
				score.base += t->top().d;
				score.type[t->top().t]++;
				t->pop();
			}
			else if (1 < Size(val(t)))
			{
				score.base += t->top().d;
				score.type[t->top().t]++;
				sushiPQ.push(t->top());
				t->pop();
			}
		}
	}

	ll ans = score.Result();
	rep(i, K, N)
	{
		if (sushiPQ.empty()) break;
		if (score.type.count(sushi[i].t) == 0)
		{
			score.base -= abs(sushiPQ.top().d - sushi[i].d);
			score.type[sushi[i].t]++;
			ans = max(ans, score.Result());
			sushiPQ.pop();
		}
	}

	cout << ans;
	return 0;
}


Measured memory_bytes: 12280