#include <bits/stdc++.h>
 
using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
// #define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(int)(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
//int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
//int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
//const ll MOD = 1000000007;
const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'


signed main() {
    ll n, k;
    cin >> n >> k;
    vector<pii> dt(n);
    rep (i, n) {
        cin >> dt[i].second >> dt[i].first;
    }
    sort(all(dt));
    reverse(all(dt));

    vector<bool> is_new(n);
    set<int> st;
    rep (i, n) {
        if (not st.count(dt[i].second)) {
            is_new[i] = true;
        }
        st.insert(dt[i].second);
    }


    int last_sushi = -1;
    ll right_new_kind = 0;
    ll sum_new_delicious = 0;
    for (int i = 0; i < n; i++) {
        if (is_new[i]) {
            last_sushi = i;
            right_new_kind++;
            sum_new_delicious += dt[i].first;
            if (right_new_kind == k) {
                break;
            }
        }
    }

    ll ans = 0;
    if (right_new_kind == k) {
        ans = k * k + sum_new_delicious;
    }

    ll left_sum = 0;
    int left_new_kind = 0;
    for (int i = 1; i <= k; i++) {
        if (is_new[i - 1]) {
            left_new_kind++;
            sum_new_delicious -= dt[i - 1].first;
        }
        left_sum += dt[i - 1].first;
        while (last_sushi >= i and (right_new_kind - left_new_kind) + i > k) {
            if (is_new[last_sushi]) {
                sum_new_delicious -= dt[last_sushi].first;
                right_new_kind--;
            }
            last_sushi--;
        }

        if ((last_sushi >= i or i == k) and (right_new_kind - left_new_kind) + i == k) {
            ans = max(ans, left_sum + sum_new_delicious + right_new_kind * right_new_kind);
        }
    }
    cout << ans << endl;
}

Measured memory_bytes: 5760