#include <limits>
#include <initializer_list>
#include <utility>
#include <bitset>
#include <tuple>
#include <type_traits>
#include <functional>
#include <string>
#include <array>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <iterator>
#include <algorithm>
#include <complex>
#include <random>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <regex>
#include <cassert>
#include <cstddef>
#define endl codeforces
#define ALL(v) std::begin(v), std::end(v)
#define ALLR(v) std::rbegin(v), std::rend(v)
using ll = std::int64_t;
using ull = std::uint64_t;
using pii = std::pair<int, int>;
using tii = std::tuple<int, int, int>;
using pll = std::pair<ll, ll>;
using tll = std::tuple<ll, ll, ll>;
template <typename T> using vec = std::vector<T>;
template <typename T> using vvec = vec<vec<T>>;
template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> const T& clamp(const T &t, const T &low, const T &high) { return std::max(low, std::min(high, t)); }
template <typename T> void chclamp(T &t, const T &low, const T &high) { return t = clamp(t, low, high); }
template <typename T> T make_v(T init) { return init; }
template <typename T, typename... Tail> auto make_v(T init, std::size_t s, Tail... tail) { auto v = std::move(make_v(init, tail...)); return vec<decltype(v)>(s, v); }
template <typename T, std::size_t Head, std::size_t ...Tail> struct multi_dem_array { using type = std::array<typename multi_dem_array<T, Tail...>::type, Head>; };
template <typename T, std::size_t Head> struct multi_dem_array<T, Head> { using type = std::array<T, Head>; };
template <typename T, std::size_t ...Args> using mdarray = typename multi_dem_array<T, Args...>::type;
namespace init__ { struct InitIO { InitIO() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(30); } } init_io; }
    
constexpr std::size_t SIZE = 80;
constexpr ll inf = 5e15;

struct Solver {
    ll n, k;
    vec<std::pair<std::string, ll>> sv;
    vvec<ll> cnts, lcost;
    mdarray<ll, 2, SIZE, SIZE> minc;
    mdarray<std::string, 2, SIZE, SIZE> substr;

    Solver(ll n, ll k) : n(n), k(k), sv(n), cnts(make_v<ll>(0, 3, n)), lcost(make_v<ll>(inf, 3, k + 1)) {
        for (ll i = 0; i < 2; i++) for (auto &&v : minc[i]) std::fill(ALL(v), inf);
        minc[0][0][0] = minc[1][0][0] = 0;
        for (ll i = 1; i < SIZE; i++) for (ll j = 1; j < SIZE; j++) {
            substr[0][i][j] = std::string(i, 'J') + std::string(j, 'O');
            substr[1][i][j] = std::string(i, 'O') + std::string(j, 'I');
        }

        ll idx = 0;
        char cs[] = { 'J', 'O', 'I', };
        for (auto &&e : sv) {
            std::string s;
            ll c;
            std::cin >> s >> c;
            e = std::make_pair(s, c);
            for (ll i = 1; i < SIZE; i++) for (ll j = 1; j < SIZE; j++) {
                if (in_s(s, substr[0][i][j])) chmin(minc[0][i][j], c);
                if (in_s(s, substr[1][i][j])) chmin(minc[1][i][j], c);
            }
            for (ll i = 0; i < 3; i++) {
                ll cnt = 0;
                for (char c : s) if (c == cs[i]) cnt++;
                cnts[i][idx] = cnt;
            }
            idx++;
        }
    }

    bool in_s(const std::string &a, const std::string &b) {
        ll idx = 0;
        for (char c : a) {
            if (c == b[idx]) idx++;
            if (idx == b.size()) break;
        }
        return idx == b.size();
    }

    void calc_lc(ll cidx) {
        lcost[cidx][0] = 0;
        for (ll i = 0; i < n; i++) {
            ll cnt = cnts[cidx][i];
            ll cost = sv[i].second;
            if (cnt == 0) continue;
            while (true) {
                for (ll j = k; 0 <= j; j--) {
                    ll pre = std::max<ll>(j - cnt, 0);
                    chmin(lcost[cidx][j], lcost[cidx][pre] + cost);
                }
                cnt *= 2;
                cost *= 2;
                if (k <= cnt) break;
            }
        }
    }

    ll solve() {
        for (ll i = 0; i < 3; i++) calc_lc(i);
        ll ans = inf;
        for (ll i = 0; i <= k; i++) for (ll j = 0; j <= k; j++) for (ll l = 0; l <= k; l++) for (ll m = 0; m <= k; m++) {
            ll tmp = 0;
            tmp += minc[0][i][j];
            tmp += minc[1][l][m];
            ll rest_j = k - i;
            ll rest_o = std::max<ll>(k - (j + l), 0);
            ll rest_i = k - m;
            tmp += lcost[0][rest_j] + lcost[1][rest_o] + lcost[2][rest_i];
            chmin(ans, tmp);
        }
        return ans == inf ? -1 : ans;
    }
};

int main() {
    ll n, k;
    std::cin >> n >> k;
    Solver solver(n, k);
    std::cout << solver.solve() << '\n';
    return 0;
}