#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template<class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i,a,n) for(int (i)=(a);(i)<(n);++(i))
#define eFOR(i,a,n) for(int (i)=(a);(i)<=(n);++(i))
#define rFOR(i,a,n) for(int (i)=(n)-1;(i)>=(a);--(i))
#define erFOR(i,a,n) for(int (i)=(n);(i)>=(a);--(i))
#define each(i, a) for(auto &i : a)
#define SORT(i) sort((i).begin(),(i).end())
#define rSORT(i,a) sort((i).begin(),(i).end(),(a))
#define all(i) (i).begin(),(i).end()
#define out(y,x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define line cout << "-----------------------------\n" 
#define ENDL(i,n) ((i) == (n) - 1 ? "\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template<class T>inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; }return false; }
template<class T>inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; }return false; }
inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); }
template<class T>inline istream& operator>>(istream& is, vector<T>& v) { for (auto& elemnt : v)is >> elemnt; return is; }
template<class T>inline istream& operator>>(istream& is, deque<T>& v) { for (auto& elemnt : v)is >> elemnt; return is; }
template<class T, class U>inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template<class T>inline vector<T> vec(size_t a) { return vector<T>(a); }
template<class T>inline vector<T> defvec(T def, size_t a) { return vector<T>(a, def); }
template<class T, class... Ts>inline auto vec(size_t a, Ts... ts) { return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...)); }
template<class T, class... Ts>inline auto defvec(T def, size_t a, Ts... ts) { return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...)); }

int sum(VI& a, int l, int r) { return (r == -1 ? a.back() : a[r - 1]) -(0 < l ? a[l - 1] : 0); }

int main() {
    init();

    int n, k; cin >> n >> k;
    VS s(n); VI c(n);
    /*
    FOR(i, 0, 100)s[0] += 'J';
    FOR(i, 0, 100)s[1] += 'O';
    FOR(i, 0, 100)s[2] += 'I';
    FOR(j, 0, n)c[j] = j * 20;
    */
    FOR(i, 0, n)cin >> s[i] >> c[i];

    vector<VI> J(n), O(n), I(n);
    FOR(i, 0, n) {
        int m = s[i].length();
        J[i].resize(m), O[i].resize(m), I[i].resize(m);
        FOR(j, 0, m) {
            if (0 < j) {
                J[i][j] += J[i][j - 1];
                O[i][j] += O[i][j - 1];
                I[i][j] += I[i][j - 1];
            }
            if (s[i][j] == 'J')++J[i][j];
            if (s[i][j] == 'O')++O[i][j];
            if (s[i][j] == 'I')++I[i][j];
        }
    }

    ll ans;
    if (80 < k) {
        VL dp(k * 3 + 1, LLINF);
        dp[0] = 0;
        FOR(i, 0, k - 80)FOR(j, 0, n) {
            int len = sum(J[j], 0, -1);
            chmin(dp[i + len], dp[i] + c[j]);
        }
        FOR(i, k - 80, k)FOR(j, 0, n) {
            if (i + sum(J[j], 0, -1) < k) {
                chmin(dp[i + sum(J[j], 0, -1)], dp[i] + c[j]);
            }
            else {
                int idx = lower_bound(all(J[j]), k - i) - J[j].begin();
                chmin(dp[k + sum(O[j], idx, -1)], dp[i] + c[j]);
            }
        }

        FOR(i, k, k * 2 - 80)FOR(j, 0, n) {
            int len = sum(O[j], 0, -1);
            chmin(dp[i + len], dp[i] + c[j]);
        }
        FOR(i, k * 2 - 80, k * 2)FOR(j, 0, n) {
            if (i + sum(O[j], 0, -1) < k * 2) {
                chmin(dp[i + sum(O[j], 0, -1)], dp[i] + c[j]);
            }
            else {
                int idx = lower_bound(all(O[j]), k * 2 - i) - O[j].begin();
                chmin(dp[min(k * 2 + sum(I[j], idx, -1), k * 3)], dp[i] + c[j]);
            }
        }

        FOR(i, k, k * 3)FOR(j, 0, n) {
            int len = sum(I[j], 0, -1);
            chmin(dp[min(i + len, k * 3)], dp[i] + c[j]);
        }

        ans = dp[k * 3];
    }
    else {
        VL dp(k * 3 + 1, LLINF);
        dp[0] = 0;
        
        FOR(i, 0, k)FOR(j, 0, n) {
            if (i + sum(J[j], 0, -1) < k) {
                chmin(dp[i + sum(J[j], 0, -1)], dp[i] + c[j]);
            }
            else {
                int idx1 = lower_bound(all(J[j]), k - i) - J[j].begin();
                if (k + sum(O[j], idx1, -1) < k * 2) {
                    chmin(dp[k + sum(O[j], idx1, -1)], dp[i] + c[j]);
                }
                else {
                    int idx2 = lower_bound(all(O[j]), k + sum(O[j], idx1, -1)) - O[j].begin();
                    chmin(dp[min(k * 2 + sum(I[j], idx2, -1), k * 3)], dp[i] + c[j]);
                }
            }
        }

        FOR(i, k, k * 2)FOR(j, 0, n) {
            if (i + sum(O[j], 0, -1) < k * 2) {
                chmin(dp[i + sum(O[j], 0, -1)], dp[i] + c[j]);
            }
            else {
                int idx = lower_bound(all(O[j]), k * 2 - i) - O[j].begin();
                chmin(dp[min(k * 2 + sum(I[j], idx, -1), k * 3)], dp[i] + c[j]);
            }
        }

        FOR(i, k * 2, k * 3)FOR(j, 0, n) {
            chmin(dp[min(i + sum(I[j], 0, -1), k * 3)], dp[i] + c[j]);
        }

        ans = dp[k * 3];
    }

    cout << (ans == LLINF ? -1 : ans) << "\n";
}