#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

const int MAX_N = 80;

int counter[MAX_N][3];
int counter_sub[MAX_N][100010][3];

int main() {
  memset(counter, 0, sizeof(counter));
  memset(counter_sub, 0, sizeof(counter_sub));

  int N, K;
  cin >> N >> K;
  string S[N];
  ll C[N];

  for (int i = 0; i < N; ++i) {
    cin >> S[i] >> C[i];
  }

  for (int i = 0; i < N; ++i) {
    string s = S[i];
    int L = s.size();

    for (int j = 0; j < L; ++j) {
      if (s[j] == 'J') {
        counter[i][0]++;
      } else if (s[j] == 'O') {
        counter[i][1]++;
      } else {
        counter[i][2]++;
      }

      for (int k = 0; k < 3; ++k) {
        counter_sub[i][j][k] = counter[i][k];
      }
    }
  }

  vector<ll> dp1(K + 1, LLONG_MAX);
  vector<ll> dp2(K + 1, LLONG_MAX);
  vector<ll> dp3(K + 1, LLONG_MAX);
  dp1[0] = 0;

  for (int d = 0; d < 2; ++d) {
    for (int i = 0; i < N; ++i) {
      for (int j = 0; j <= K; ++j) {
        if (dp1[j] == LLONG_MAX) continue;

        int nj = j + counter[i][0];
        if (nj < K) {
          dp1[nj] = min(dp1[nj], dp1[j] + C[i]);
        } else {
          int idx = 0;
          while (j + counter_sub[i][idx][0] < K) {
            ++idx;
          }
          int o_cnt = counter[i][1] - counter_sub[i][idx][1];
          dp2[o_cnt] = min(dp2[o_cnt], dp1[j] + C[i]);
        }
      }
    }
  }

  for (int d = 0; d < 2; ++d) {
    for (int i = 0; i < N; ++i) {
      for (int j = 0; j <= K; ++j) {
        if (dp2[j] == LLONG_MAX) continue;

        int nj = j + counter[i][1];
        if (nj < K) {
          dp2[nj] = min(dp2[nj], dp2[j] + C[i]);
        } else {
          int idx = 0;
          while (j + counter_sub[i][idx][1] < K) {
            ++idx;
          }
          int i_cnt = counter[i][2] - counter_sub[i][idx][2];
          dp3[i_cnt] = min(dp3[i_cnt], dp2[j] + C[i]);
        }
      }
    }
  }

  for (int i = 0; i < N; ++i) {
    for (int j = 0; j <= K; ++j) {
      if (dp3[j] == LLONG_MAX) continue;

      int nj = j + counter[i][2];
      if (nj < K) {
        dp3[nj] = min(dp3[nj], dp3[j] + C[i]);
      } else {
        dp3[K] = min(dp3[K], dp3[j] + C[i]);
      }
    }
  }

  if (dp3[K] == LLONG_MAX) {
    cout << -1 << endl;
  } else {
    cout << dp3[K] << endl;
  }

  return 0;
}