#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(int i = (N) - 1; i >= 0; i--)
#define rep1(i,N) for(int i = 1; i <= (N) ; i++)
#define repr1(i,N) for(int i = (N) ; i > 0 ; i--)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
using namespace std; void solve();
using ll = long long; using vl = vector<ll>;
using vi = vector<int>; using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = (1LL << 61) - 1;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
  int main(){solve();}
#endif
using P = pair<int,int>; using vp = vector<P>;
constexpr int MOD = /**/ 1000000007; //*/ 998244353;
/////////

void solve(){
  ini(N , K);
  vp p(N); in(p);
  
  int M , m;
  // 種類数のcnt
  {
    set<int> s;
    each(x , p) s.insert(x.first);
    M = s.size();
  }
  
  auto f = [](P a,P b){return a.se > b.se;};
  vl ans(K + 1 , -infLL);
  vvi cnt(N + 1);
  set<int> s;

  sort(all(p),f);
  ll cur = 0;
  rep(i , K){
    cur += p[i].se;
    cnt[p[i].fi].pb(p[i].se);
    s.insert(p[i].fi);
  }

  ans[m = s.size()] = cur;
  
  priority_queue<P , vector<P> , decltype(f)> Q(f);
  each(i , s){
    if(cnt[i].size() > 1){
      sort(all(cnt[i]) , greater<int>());
      rep1(j , (int)cnt[i].size() - 1) Q.push( P( i , cnt[i][j]) );
    }
  }
  
  auto g = [](P a, P b){return a.se < b.se;};
  priority_queue<P , vector<P> , decltype(g)> Q2(g);
  for(int i = K; i < N ; i++) Q2.push(p[i]);

  for(int i = s.size() + 1 ; i <= min(M , K) ; i++){
    auto x = Q.top(); Q.pop();
    cur -= x.second;
    P nxt;
    do{ nxt = Q2.top(); Q2.pop(); }while(s.find(nxt.first) != s.end());
    cur += nxt.second; s.insert(nxt.first);
    ans[i] = cur;
  }

  ll bns = -inf;
  for(ll i = m; i <= min(M , K); i++){
    amax(bns , ans[i] + i * i);
  }
  out(bns);
  
  


}

Measured memory_bytes: 9596