#include <algorithm>
#include <array>
#include <bitset>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <queue>

using namespace std;

struct BoolName : numpunct<char> {
  string t, f;
  BoolName (string t = "Yes", string f = "No") : t(t), f(f) {}
  string do_truename() const {return t;}
  string do_falsename() const {return f;}
};

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15) << boolalpha;
    cout.imbue(locale(cout.getloc(), new BoolName));
  }
} initializer;

template<typename T> istream& operator>>(istream &s, vector<T> &v) {
  for (T &t : v) s >> t;
  return s;
}

template<typename T> ostream& operator<<(ostream &s, const vector<T> &v) {
  for (const T &t : v) s << t << endl;
  return s;
}

void set_bool_name(string t, string f) {
  cout.imbue(locale(cout.getloc(), new BoolName(t, f)));
}

template<typename T> bool chmin(T& a, T b) {return a > b ? a = b, true : false;}

template<typename T> bool chmax(T& a, T b) {return a < b ? a = b, true : false;}

template<typename T> void sort(vector<T>& v) {sort(v.begin(), v.end());}

template<typename T> T min(const vector<T>& v) {return *min_element(v.begin(), v.end());}

template<typename T> T max(const vector<T>& v) {return *max_element(v.begin(), v.end());}

template<typename T> int min_element(vector<T>& v) {return min_element(v.begin(), v.end()) - v.begin();}

template<typename T> int max_element(vector<T>& v) {return max_element(v.begin(), v.end()) - v.begin();}

template<typename T, typename Function> void sort(vector<T>& v, Function func) {sort(v.begin(), v.end(), func);}

template<typename T> void rsort(vector<T>& v) {sort(v.rbegin(), v.rend());}

template<typename T> void reverse(vector<T>& v) {reverse(v.begin(), v.end());}

template<typename T> void unique(vector<T>& v) {v.erase(unique(v.begin(), v.end()), v.end());}

template<typename T> void nth_element(vector<T>& v, int n) {nth_element(v.begin(), v.begin() + n, v.end());}

template<typename T> bool next_permutation(vector<T>& v) {return next_permutation(v.begin(), v.end());}

template<typename T> int find(vector<T>& v, T t) {return find(v.begin(), v.end(), t) - v.begin();}

template<typename T, typename S> int in(T v, S t) {return find(v.begin(), v.end(), t) != v.end();}

template<typename T> int lower_bound(vector<T>& v, T t) {return lower_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T> int upper_bound(vector<T>& v, T t) {return upper_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T, typename S = typename T::value_type, typename BinaryOperation> S accumulate(const T& v, S init, BinaryOperation func) {
  return accumulate(v.begin(), v.end(), init, func);
}

template<typename T, typename S = typename T::value_type> S accumulate(const T& v, S init = 0) {
  return accumulate(v.begin(), v.end(), init);
}

template<typename T> void adjacent_difference(vector<T>& v) {adjacent_difference(v.begin(), v.end(), v.begin());}

template<typename T> void adjacent_difference(vector<T>& v, vector<T>& u) {adjacent_difference(v.begin(), v.end(), u.begin());}

template<typename T> vector<T> partial_sum(const vector<T>& v) {
  vector<T> u(v.size());
  partial_sum(v.begin(), v.end(), u.begin());
  return u;
}

template<typename T> T inner_product(vector<T>& v, vector<T>& u) {return inner_product(v.begin(), v.end(), u.begin(), T(0));}

template<typename T> int count(const T& v, typename T::value_type t) {return count(v.begin(), v.end(), t);}

template<typename T, typename Function> int count_if(const vector<T>& v, Function func) {return count_if(v.begin(), v.end(), func);}

template<typename T, typename Function> void remove_if(vector<T>& v, Function func) {v.erase(remove_if(v.begin(), v.end(), func), v.end());}

template<typename T, typename Function> bool all_of(vector<T> v, Function func) {return all_of(v.begin(), v.end(), func);}

template<typename T, typename Function> bool any_of(vector<T> v, Function func) {return any_of(v.begin(), v.end(), func);}

template<typename T, typename Function> bool none_of(vector<T> v, Function func) {return none_of(v.begin(), v.end(), func);}

template<typename T> vector<T> subvector(vector<T>& v, int a, int b) {return vector<T>(v.begin() + a, v.begin() + b);}

template<typename T> int kinds(const T& v) {return set<typename T::value_type>(v.begin(), v.end()).size();}

template<typename T> map<typename T::value_type, int> count_kinds(const T& v) {
  map<typename T::value_type, int> res;
  for (const auto& i : v) ++res[i];
  return res;
}

template<typename T> void iota(vector<T>& v, T t = 0) {iota(v.begin(), v.end(), t);}

template<typename T> bool is_sorted(const vector<T>& v) {return is_sorted(v.begin(), v.end());}

template<typename T> int least_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_ffs(n) - 1;
  if (sizeof(T) == 8) return __builtin_ffsll(n) - 1;
}

// n must be greater than 0.
template<typename T> int least_bit_fast(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_ctz(n);
  if (sizeof(T) == 8) return __builtin_ctzll(n);
}

template<typename T> int most_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return n ? 31 - __builtin_clz(n) : -1;
  if (sizeof(T) == 8) return n ? 63 - __builtin_clzll(n) : -1;
}

template<typename T> int count_bit(T n) {
  static_assert(sizeof(T) == 4 || sizeof(T) == 8, "unsupported size");
  if (sizeof(T) == 4) return __builtin_popcount(n);
  if (sizeof(T) == 8) return __builtin_popcountll(n);
}

template<typename T = double> constexpr T pi() {return acos(T(-1));}

template<typename T> T gcd(T t) {return abs(t);}

template<typename T, typename... S> T gcd(T a, S... s) {
  a = abs(a);
  auto b = gcd(s...);
  if (a == 0 || b == 0) return max(a, b);
  int fa = least_bit_fast(a);
  int fb = least_bit_fast(b);
  a >>= fa;
  b >>= fb;
  while (a != b) {
    auto& c = a > b ? a : b;
    c = abs(a - b);
    c >>= least_bit_fast(c);
  }
  return a << min(fa, fb);
}

template<typename T> T gcd(const vector<T>& v) {
  T g = abs(v[0]);
  for (int i = 1; i < int(v.size()); ++i) g = gcd(g, v[i]);
  return g;
}

template<typename T> T lcm(T t) {return abs(t);}

template<typename T, typename... S> T lcm(T t, S... s) {
  T l = lcm(s...);
  return abs(t) / gcd(t, l) * l;
}

template<typename T> T lcm(const vector<T>& v) {
  T l = abs(v[0]);
  for (int i = 1; i < int(v.size()); ++i) l = lcm(l, v[i]);
  return l;
}

template<typename T> T floor(T a, T b) {
  auto d = div(a, b);
  return d.quot - (d.rem && (a < 0) != (b < 0) ? 1 : 0);
}

template<typename T> T ceil(T a, T b) {
  auto d = div(a, b);
  return d.quot + (d.rem && (a > 0) == (b > 0) ? 1 : 0);
}

template<typename T> T round(T a, T b) {return floor(a + b / 2, b);}

template<typename T> T mod(T a, T b) {
  T c = a % b;
  return c < 0 ? c + abs(b) : c;
}

template<typename T> T factorial(T n) {return n <= 1 ? 1 : factorial(n - 1) * n;}

template<typename T> vector<T> factorial_vector(int n) {
  vector<T> v(n + 1, 1);
  for (int i = 1; i <= n; ++i) v[i] = v[i - 1] * i;
  return v;
}

template<typename T> T square(T n) {return n * n;}

template<typename T> T cube(T n) {return n * n * n;}

template<typename T> T norm(T x1, T y1, T x2, T y2) {return square(x1 - x2) + square(y1 - y2);}

template<typename T> bool isSquare(T n) {return square(T(sqrt(n))) == n;}

template<typename T> T clamp(T v, T l, T u) {return v < l ? l : v > u ? u : v;}

int main() {
  int n, k;
  cin >> n >> k;
  vector<pair<int, int>> s(n);
  for (int i = 0; i < n; ++i) cin >> s[i].second >> s[i].first;
  rsort(s);
  int64_t res = 0;
  set<int> t;
  priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> que;
  for (int i = 0; i < k; ++i) {
    res += s[i].first;
    if (t.count(s[i].second)) que.emplace(s[i]);
    else t.emplace(s[i].second);
  }
  res += square<int64_t>(t.size());
  auto r = res;
  for (int i = k; i < n && !que.empty(); ++i) {
    if (t.count(s[i].second)) continue;
    t.emplace(s[i].second);
    r -= que.top().first;
    que.pop();
    r += s[i].first + 2 * t.size() - 1;
    chmax(res, r);
  }
  cout << res << endl;
}



Measured memory_bytes: 4476