/* -*- coding: utf-8 -*-
 *
 * 1029.cc:  No.1029 JJOOII 3 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 80;
const int MAX_S = 80;
const int CN = 3;
const int MAX_K = 100000;
const long long LINF = 1LL << 62;

enum { J, O, I, FIN };

/* typedef */

typedef long long ll;
typedef pair<int,int> pii;

/* global variables */

int cmap[128];
char s[MAX_S + 4];
int cs[MAX_N], scs[CN][MAX_S], scns[CN];
pii ps[MAX_N][CN + 1][MAX_K];
ll dp[CN + 1][MAX_K];

/* subroutines */

inline void setmin(ll &a, ll b) { if (a > b) a = b; }

/* main */

int main() {
  cmap['J'] = J, cmap['O'] = O, cmap['I'] = I;

  int n, k;
  scanf("%d%d", &n, &k);

  for (int i = 0; i < n; i++) {
    scanf("%s%d", s, cs + i);
    int sn = strlen(s);

    memset(scns, 0, sizeof(scns));
    for (int j = 0; j < sn; j++) {
      int sj = cmap[s[j]];
      scs[sj][scns[sj]++] = j;
    }

    for (int l = 0; l < k; l++) ps[i][FIN][l] = pii(FIN, 0);
    for (int j = FIN - 1; j >= 0; j--)
      for (int l = k - 1; l >= 0; l--) {
	int z = j, y = l, x = 0;
	while (z < FIN) {
	  int q = lower_bound(scs[z], scs[z] + scns[z], x) - scs[z];
	  int yy = y + (scns[z] - q);
	  if (yy < k) {
	    ps[i][j][l] = pii(z, yy);
	    break;
	  }
	  int xq = q + (k - y);
	  x = scs[z][xq - 1] + 1;
	  y = 0;
	  z++;
	}
	if (z == FIN) ps[i][j][l] = pii(FIN, 0);
      }
    //printf("%d\n", i);
    //for (int j = 0; j <= FIN; j++) {
    //for (int l = 0; l < k; l++)
    //printf(" (%d,%d)", ps[i][j][l].first, ps[i][j][l].second);
    //putchar('\n');
    //}
  }

  for (int j = 0; j <= FIN; j++) fill(dp[j], dp[j] + k, LINF);
  dp[0][0] = 0;

  for (int j = 0; j < FIN; j++)
    for (int l = 0; l < k; l++)
      if (dp[j][l] < LINF)
	for (int i = 0; i < n; i++) {
	  int j1 = ps[i][j][l].first, l1 = ps[i][j][l].second;
	  if (j1 != j || l1 != l)
	    setmin(dp[j1][l1], dp[j][l] + cs[i]);
	}
  
  printf("%lld\n", (dp[FIN][0] >= LINF) ? -1 : dp[FIN][0]);
  return 0;
}