#include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;
// const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

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

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}


int main() {
  int N, K;
  cin >> N >> K;
  //同じ文字列を何個買ってもいい　了解！
  vector< string > S(N);
  vector< int > C(N);
  vector< int > J(N), O(N), I(N);
  for(int i = 0; i < N; i++) {
    cin >> S[i] >> C[i];
    for(auto &c : S[i]) J[i] += c == 'J';
    for(auto &c : S[i]) O[i] += c == 'O';
    for(auto &c : S[i]) I[i] += c == 'I';
  }
  auto dp = make_v< int64 >(K * 3 + 1);
  fill_v(dp, infll);
  dp[0] = 0;
  for(int i = 0; i < K * 3; i++) {
    for(int j = 0; j < N; j++) {
      int pos = i;
      if(pos + J[j] < K) {
        chmin(dp[pos + J[j]], dp[i] + C[j]);
      } else if(K <= pos && pos + O[j] < 2 * K) {
        chmin(dp[pos + O[j]], dp[i] + C[j]);
      } else if(2 * K <= pos) {
        chmin(dp[min(3 * K, pos + I[j])], dp[i] + C[j]);
      } else {
        for(auto &c : S[j]) {
          if(pos < K) pos += c == 'J';
          else if(pos < 2 * K) pos += c == 'O';
          else if(pos < 3 * K) pos += c == 'I';
        }
        chmin(dp[pos], dp[i] + C[j]);
      }
    }
  }
  if(dp.back() >= infll) dp.back() = -1;
  cout << dp.back() << endl;
}