#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define REP(i, n) FOR(i,0,n)

template<typename T>
struct ShortestPath
{
    int V, E;
    int INVALID = -1;
    std::vector<std::vector<std::pair<int, T>>> to;
    ShortestPath() = default;
    ShortestPath(int V) : V(V), E(0), to(V) {}
    void add_edge(int s, int t, T len) {
        assert(0 <= s and s < V);
        assert(0 <= t and t < V);
        to[s].emplace_back(t, len);
        E++;
    }

    std::vector<T> dist;
    std::vector<int> prev;
    // Dijkstra algorithm
    // Complexity: O(E log E)
    void Dijkstra(int s) {
        assert(0 <= s and s < V);
        dist.assign(V, std::numeric_limits<T>::max());
        dist[s] = 0;
        prev.assign(V, INVALID);
        using P = std::pair<T, int>;
        std::priority_queue<P, std::vector<P>, std::greater<P>> pq;
        pq.emplace(0, s);
        while(!pq.empty()) {
            T d;
            int v;
            std::tie(d, v) = pq.top();
            pq.pop();
            if (dist[v] < d) continue;
            for (auto nx : to[v]) {
                T dnx = d + nx.second;
                if (dist[nx.first] > dnx) {
                    dist[nx.first] = dnx, prev[nx.first] = v;
                    pq.emplace(dnx, nx.first);
                }
            }
        }
    }
};

int main()
{
    int N, K;
    cin >> N >> K;
    ShortestPath<lint> graph(K * 3 + 1);
    while (N--)
    {
        string S;
        lint C;
        cin >> S >> C;
        REP(i, K * 3)
        {
            int now = i;
            for (auto c : S)
            {
                if (now < K and c == 'J') now++;
                if (now >= K and now < K * 2 and c == 'O') now++;
                if (now >= K * 2 and now < K * 3 and c == 'I') now++;
            }
            graph.add_edge(i, now, C);
        }
    }
    graph.Dijkstra(0);
    cout << (graph.dist.back() > 4e18 ? -1 : graph.dist.back()) << '\n';
}