#pragma GCC optimize("Ofast", "unroll-loops", "omit-frame-pointer", "inline")
#pragma GCC option("arch=native", "tune=native", "no-zero-upper")
#pragma GCC target("avx2")

#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() {
  const int N = 80;
  int n, k; cin >> n >> k;
  string s[N];
  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;
    }
  }
  ll dp[300001];
  REP(i, k * 3 + 1) dp[i] = 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;
    for (char c : s[j]) {
      if (status == 0) {
        if (c == 'J') ++cnt;
      } else if (status == 1) {
        if (c == 'O') ++cnt;
      } else if (status == 2) {
        if (c == 'I') ++cnt;
      }
      if (cnt == k && status < 2) {
        status = status + 1;
        cnt = 0;
      }
    }
    chmin(cnt, k);
    chmin(dp[status * k + cnt], dp[i] + c[j]);
  }
  cout << dp[k * 3] << '\n';
  return 0;
}