#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> bool chmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }


int main()
{
    int N, K;
    cin >> N >> K;
    vector<string> S(N);
    vector<lint> C(N);
    REP(i, N) cin >> S[i] >> C[i];
    vector<int> cntj(N), cnto(N), cnti(N);
    REP(i, N) for (auto c : S[i])
    {
        if (c == 'J') cntj[i]++;
        if (c == 'O') cnto[i]++;
        if (c == 'I') cnti[i]++;
    }

    vector<lint> cost(K * 3 + 1, 9e18);
    cost[0] = 0;
    REP(i, K * 3) if (cost[i] < cost[i + 1])
    {
        REP(j, N)
        {
            if (i + 100 < K) chmin(cost[i + cntj[j]], cost[i] + C[j]);
            else if (i >= K and i + 100 < K * 2) chmin(cost[i + cnto[j]], cost[i] + C[j]);
            else if (i >= K * 2 and i + 100 < K * 3) chmin(cost[i + cnti[j]], cost[i] + C[j]);
            else
            {
                int now = i;
                for (auto c : S[j])
                {
                    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++;
                }
                cost[now] = min(cost[now], cost[i] + C[j]);
            }
        }
    }
    cout << (cost.back() == 9e18 ? -1 : cost.back()) << '\n';
}