#line 1 "main.cpp"
#include <bits/stdc++.h>
#line 2 "/home/user/GitHub/competitive-programming-library/utils/macros.hpp"
#define REP(i, n) for (int i = 0; (i) < (int)(n); ++ (i))
#define REP3(i, m, n) for (int i = (m); (i) < (int)(n); ++ (i))
#define REP_R(i, n) for (int i = (int)(n) - 1; (i) >= 0; -- (i))
#define REP3R(i, m, n) for (int i = (int)(n) - 1; (i) >= (int)(m); -- (i))
#define ALL(x) std::begin(x), std::end(x)
#line 4 "/home/user/GitHub/competitive-programming-library/utils/binary_search.hpp"

/**
 * @brief a binary search / 二分探索
 * @param[in] p  a monotone predicate defined on $[l, r)$
 * @return $\min \lbrace x \in [l, r) \mid p(x) \rbrace$, or r if it doesn't exist
 */
template <typename UnaryPredicate>
int64_t binsearch(int64_t l, int64_t r, UnaryPredicate p) {
    assert (l <= r);
    -- l;
    while (r - l > 1) {
        int64_t m = l + (r - l) / 2;
        (p(m) ? r : l) = m;
    }
    return r;
}

/**
 * @return $\max \lbrace x \in (l, r] \mid p(x) \rbrace$, or l if it doesn't exist
 */
template <typename UnaryPredicate>
int64_t binsearch_max(int64_t l, int64_t r, UnaryPredicate p) {
    assert (l <= r);
    ++ r;
    while (r - l > 1) {
        int64_t m = l + (r - l) / 2;
        (p(m) ? l : r) = m;
    }
    return l;
}
#line 4 "main.cpp"
using namespace std;
template <class T, class U> inline void chmin(T & a, U const & b) { a = min<T>(a, b); }


int64_t solve(int n, int k, const vector<string> & s, const vector<int64_t> & cost) {
    vector<vector<int> > acc_a(n);
    vector<vector<int> > acc_b(n);
    vector<vector<int> > acc_c(n);
    REP (i, n) {
        acc_a[i].resize(s[i].size() + 1);
        acc_b[i].resize(s[i].size() + 1);
        acc_c[i].resize(s[i].size() + 1);
        REP (j, s[i].size()) {
            acc_a[i][j + 1] = acc_a[i][j] + (s[i][j] == 'J');
            acc_b[i][j + 1] = acc_b[i][j] + (s[i][j] == 'O');
            acc_c[i][j + 1] = acc_c[i][j] + (s[i][j] == 'I');
        }
    }

    vector<int64_t> dp(3 * k + 1, INT64_MAX);
    dp[0] = 0;
    REP (j, k) if (dp[j] != INT64_MAX) {
        REP (i, n) {
            int m = s[i].size();
            int l = 0;
            int r = binsearch(l, m, [&](int r) {
                return j + acc_a[i][r] - acc_a[i][l] >= k;
            });
            int nj;
            if (r == m) {
                nj = j + acc_a[i][r] - acc_a[i][l];
            } else {
                l = r;
                r = binsearch(l, m, [&](int r) {
                    return acc_b[i][r] - acc_b[i][l] >= k;
                });
                if (r == m) {
                    nj = k + acc_b[i][r] - acc_b[i][l];
                } else {
                    l = r;
                    r = m;
                    nj = 2 * k + min(k, acc_c[i][r] - acc_c[i][l]);
                }
            }
            chmin(dp[nj], dp[j] + cost[i]);
        }
    }
    REP (j, k) if (dp[k + j] != INT64_MAX) {
        REP (i, n) {
            int m = s[i].size();
            int l = 0;
            int r = binsearch(l, m, [&](int r) {
                return j + acc_b[i][r] - acc_b[i][l] >= k;
            });
            int nj;
            if (r == m) {
                nj = k + j + acc_b[i][r] - acc_b[i][l];
            } else {
                l = r;
                r = m;
                nj = 2 * k + min(k, acc_c[i][r] - acc_c[i][l]);
            }
            chmin(dp[nj], dp[k + j] + cost[i]);
        }
    }
    REP (j, k) if (dp[2 * k + j] != INT64_MAX) {
        REP (i, n) {
            int m = s[i].size();
            int l = 0;
            int r = m;
            int nj = 2 * k + min(k, j + acc_c[i][r] - acc_c[i][l]);
            chmin(dp[nj], dp[2 * k + j] + cost[i]);
        }
    }
    return dp.back();
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    constexpr char endl = '\n';
    int N;
    int K;
    cin >> N;
    vector<string> S(N);
    vector<int64_t> C(N);
    cin >> K;
    REP (i, N) {
        cin >> S[i] >> C[i];
    }
    auto ans = solve(N, K, S, C);
    cout << (ans == INT64_MAX ? -1 : ans) << endl;
    return 0;
}