#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)

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<lint> cost(K * 3 + 1, 9e18);
    cost[0] = 0;
    REP(i, K * 3)
    {
        if (cost[i] == 9e18)
        {
            puts("-1");
            return 0;
        }
        REP(j, N)
        {
            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() << '\n';
}