#include <algorithm>
#include <cmath>
#include <complex>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <vector>
#include <functional>
#include <cstring>
#include <regex>
#include <random>
#include <cassert>
#include <stack>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, s, n) for (int i = (s); i < (int)(n); i++)
#define revrep(i, n) for (int i = (n) - 1; i >= 0; i--)
#define revrepr(i, s, n) for (int i = (n) - 1; i >= s; i--)
#define debug(x) cerr << #x << ": " << x << "\n"
#define popcnt(x) __builtin_popcount(x)

const double PI = acos(-1.0);

using ll = long long;
using P = pair<int, int>;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

template<class T>
istream& operator >>(istream &is, vector<T> &v) {
    for (int i = 0; i < (int)v.size(); i++) cin >> v.at(i);
    return is;
}

template<class T, class U>
ostream& operator <<(ostream &os, pair<T, U> p) {
    cout << '(' << p.first << ", " << p.second << ')';
    return os;
}

template<class T>
void print(const vector<T> &v, const string &delimiter) { rep(i, v.size()) cout << (0 < i ? delimiter : "") << v.at(i); cout << endl; }

template<class T>
void print(const vector<vector<T>> &vv, const string &delimiter) { for (const auto &v: vv) print(v, delimiter); }


int main() {
    int n, k;
    cin >> n >> k;
    vector<string> s(n);
    vector<ll> c(n);
    rep(i, n) cin >> s[i] >> c[i];
    
    string JOI = "JOI";
    vector<vector<int>> cnt(n, vector<int>(3));
    rep(i, n) {
        for (char c: s[i]) rep(j, 3) if (c == JOI[j]) cnt[i][j]++;
    }
    
    const ll INF = 1e18;
    vector<ll> dp(k * 3 + 1, INF);
    dp[0] = 0;
    
    string t;
    rep(i, 3) rep(j, k) t += JOI[i];
    
    rep(i, k * 3) {
        int idx = i / k;
        rep(j, n) {
            if (t[i] != t[min(k * 3 - 1, i + cnt[j][idx])]) {
                if (idx == 0) {
                    int rem_J = k - i;
                    int cnt_O = 0;
                    int cnt_I = 0;
                    for (char c: s[j]) {
                        if (rem_J == 0) {
                            if (k == cnt_O) {
                                if (c == 'I') cnt_I++;
                            }
                            else if (c == 'O') cnt_O++;
                        }
                        else {
                            if (c == 'J') rem_J--;
                        }
                    }
                    chmin(dp[k + min(k, cnt_O) + min(k, cnt_I)], dp[i] + c[j]);
                }
                else {
                    int rem_O = k * 2 - i;
                    int cnt_I = 0;
                    for (char c: s[j]) {
                        if (rem_O == 0) {
                            if (c == 'I') cnt_I++;
                        }
                        else if (c == 'O') rem_O--;
                    }
                    chmin(dp[k * 2 + min(k, cnt_I)], dp[i] + c[j]);
                }
            }
            else {
                chmin(dp[min(k * 3, i + cnt[j][idx])], dp[i] + c[j]);
            }
        }
    }
    
    if (dp[k * 3] != INF) cout << dp[k * 3] << endl;
    else cout << -1 << endl;
}