#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    int n, k;
    cin >> n >> k;
    string s[n];
    ll c[n];
    rep(i,n)cin >> s[i] >> c[i];
    ll dp[k*3];
    rep(i,k*3)dp[i] = 1001001001001001001;

    int f[n][3] = {};
    int m[n];
    rep(i,n){
        m[i] = s[i].size();
        rep(j,n){
            if(s[i][j] == 'J')f[i][0]++;
            if(s[i][j] == 'O')f[i][1]++;
            if(s[i][j] == 'I')f[i][2]++;
        }
    }

    rep(i,k*3){
        rep(j,n){
            if(k > 200 && 100 <= i && i < k){
                dp[i] = min(dp[i], dp[i-f[j][0]] + c[j]);
            }else if(k > 200 && k + 100 <= i && i < k*2){
                dp[i] = min(dp[i], dp[i-f[j][1]] + c[j]);
            }else if(k > 200 && k*2 + 100 <= i && i < k*3){
                dp[i] = min(dp[i], dp[i-f[j][2]] + c[j]);
            }else{
                int now = i;
                drep(l,m[j]){
                    if(now == -1)break;
                    char x = 'J';
                    if(now >= k)x = 'O';
                    if(now >= k*2)x = 'I';
                    if(s[j][l] == x)now--;
                }
                if(now == -1)dp[i] = min(dp[i], c[j]);
                else dp[i] = min(dp[i], dp[now] + c[j]);
            }
        }
    }

    ll ans = dp[k*3-1];
    if(ans == 1001001001001001001)ans = -1;
    cout << ans << endl;
    return 0;
}