#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n, k; cin >> n >> k;
  vector<string> s(n);
  vector<int> c(n);
  REP(i, n) cin >> s[i] >> c[i];
  {
    bool j = false, o = false, I = false;
    REP(i, n) for (char c : s[i]) {
      j |= c == 'J';
      o |= c == 'O';
      I |= c == 'I';
    }
    // cout << j << ' ' << o << ' ' << i << '\n';
    if (!j || !o || !I) {
      cout << "-1\n";
      return 0;
    }
  }
  map<char, int> mp;
  mp['J'] = 0; mp['O'] = 1; mp['I'] = 2;
  vector<vector<vector<int>>> sum(n);
  REP(i, n) {
    int m = s[i].length();
    sum[i] = vector(3, vector(m, 0));
    REP(j, 3) REP(l, m) {
      if (l > 0) sum[i][j][l] += sum[i][j][l - 1];
      sum[i][j][l] += mp[s[i][l]] == j;
    }
  }
  vector<ll> dp(k * 3 + 1, LINF);
  dp[0] = 0;
  REP(i, k * 3) REP(j, n) {
    int status, cnt = i % k;
    if (i < k) status = 0;
    if (k <= i && i < k * 2) status = 1;
    if (k * 2 <= i) status = 2;
    int r = -1;
    REP(l, 3) {
      if (r == s[j].length()) break;
      int nx = lower_bound(sum[j][status].begin() + r + 1, sum[j][status].end(), k - cnt + (r == -1 ? 0 : sum[j][status][r])) - sum[j][status].begin();
      if (nx == s[j].length()) {
        cnt += sum[j][status][s[j].length() - 1] - (r == -1 ? 0 : sum[j][status][r]);
        r = s[j].length();
      } else {
        cnt = k;
        if (status < 2) {
          ++status;
          cnt = 0;
        }
        r = nx;
      }
    }
    chmin(cnt, k);
    chmin(dp[status * k + cnt], dp[i] + c[j]);
  }
  cout << dp[k * 3] << '\n';
  return 0;
}