#include <bits/stdc++.h>  // clang-format off
using Int = long long;
#define REP_(i, a_, b_, a, b, ...) for (Int i = (a), lim##i = (b); i < lim##i; i++)
#define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
struct SetupIO { SetupIO() { std::cin.tie(nullptr), std::ios::sync_with_stdio(false), std::cout << std::fixed << std::setprecision(13); } } setup_io;
#ifndef _MY_DEBUG
#define dump(...)
#endif  // clang-format on

/**
 *    author:  knshnb
 *    created: Fri Apr 17 21:50:59 JST 2020
 **/

template <class T, class S> T make_vec(S x) { return x; }
template <class T, class... Ts> auto make_vec(size_t n, Ts... ts) {
    return std::vector<decltype(make_vec<T>(ts...))>(n, make_vec<T>(ts...));
}

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

const Int INF = 2e18;
signed main() {
    Int n, K;
    std::cin >> n >> K;
    std::string T(3 * K + 100, '$');
    REP(i, K) T[i] = 'J';
    REP(i, K, 2 * K) T[i] = 'O';
    REP(i, 2 * K, 3 * K) T[i] = 'I';
    std::vector<std::pair<std::string, Int>> ps(n);
    REP(i, n) std::cin >> ps[i].first >> ps[i].second;
    auto cnt = make_vec<Int>(n, 3, 0);
    REP(i, n) {
        for (char c : ps[i].first) {
            cnt[i][0] += c == 'J';
            cnt[i][1] += c == 'O';
            cnt[i][2] += c == 'I';
        }
    }
    std::vector<Int> dp(3 * K + 100, INF);
    dp[0] = 0;
    REP(i, 3 * K) {
        REP(k, n) {
            auto& p = ps[k];
            Int j = i, idx = 0;
            std::string& s = p.first;
            if (i + cnt[k][i / K] < K * (i / K + 1)) {
                j = i + cnt[k][i / K];
            } else {
                while (1) {
                    idx = std::find(s.begin() + idx, s.end(), T[j]) - s.begin() + 1;
                    if (idx > s.size()) break;
                    j++;
                }
            }
            chmin(dp[j], dp[i] + p.second);
        }
    }
    std::cout << (dp[3 * K] == INF ? -1 : dp[3 * K]) << std::endl;
}