#include <bits/stdc++.h>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
// const ll mod = 998244353;
const ll INF = mod * mod;
const int INF_N = 1e+9;
typedef pair<int, int> P;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

//繰り返し二乗法
ll mod_pow(ll a, ll n, ll m) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%m;
		a = a * a%m; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

//逆元(Eucledean algorithm)
ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
using mP = pair<modint, modint>;

int dx[4] = { 0,1,0,-1 };
int dy[4] = { 1,0,-1,0 };




void solve() {
    ll n, k; cin >> n >> k;
    vector<string> s(n);
    vector<ll> c(n);
    rep(i, n) cin >> s[i] >> c[i];

    ll jc, oc, ic, jp, op, ip;
    jc = oc = ic = 1;
    jp = op = ip = INF;
    rep(i, n){
        string ss = s[i];
        ll cc = c[i];
        ll tjc = count(all(ss), 'J');
        ll toc = count(all(ss), 'O');
        ll tic = count(all(ss), 'I');

        if(tjc != 0){
            if(cc*jc < jp*tjc){
                jc = tjc;
                jp = cc;
            }
        }
        if(toc != 0){
            if(cc*oc < op*toc){
                oc = toc;
                op = cc;
            }
        }
        if(tic != 0){
            if(cc*ic < ip*tic){
                ic = tic;
                ip = cc;
            }
        }
    }

    if(jp == INF || op == INF || ip == INF){
        cout << -1 << endl;
        return;
    }

    map<ll, ll> mo, mi;
    rep(i, n){
        string ss = s[i];
        ll tjc = count(all(ss), 'J');
        ll tc = (k-tjc+jc-1)/jc; 
        ll st = k-tc*jc;
        ll tp = tc*jp;
        ll od = 0;
        rep(j, ss.size()){
            if(st <= 0){
                if(ss[j] == 'O') od++;
            }else{
                if(ss[j] == 'J') st--;
            }
        }
        if(mo.count(od)){
            mo[od] = min(mo[od], tp+c[i]);
        }else{
            mo[od] = tp+c[i];
        }
    }

    for(auto p: mo){
        rep(i, n){
            string ss = s[i];
            ll toc = count(all(ss), 'O');
            ll tc = (k-p.first-toc+oc-1)/oc; 
            ll st = k-tc*oc;
            ll tp = tc*op;
            ll id = 0;
            rep(j, ss.size()){
                if(st <= 0){
                    if(ss[j] == 'I') id++;
                }else{
                    if(ss[j] == 'O') st--;
                }
            }
            if(mi.count(id)){
                mi[id] = min(mi[id], p.second+tp+c[i]);
            }else{
                mi[id] = p.second+tp+c[i];
            }
        }
    }

    ll res = INF;
    for(auto p: mi){
        res = min(res, p.second + (k-p.first+ip-1)/ip*ip);
    }

    cout << res << endl;
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  //cout << fixed << setprecision(10);
  //init_f();
  //init();
  //int t; cin >> t; rep(i, t)solve();
  solve();
//   stop
    return 0;
}