import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


enum INF = 10L^^18;

void main() {
  try {
    for (; ; ) {
      const N = readInt();
      const K = readInt();
      auto S = new string[N];
      auto C = new long[N];
      foreach (i; 0 .. N) {
        S[i] = readToken();
        C[i] = readLong();
      }
      
      auto L = new int[N];
      auto counts = new int[][][](3, N);
      foreach (i; 0 .. N) {
        L[i] = cast(int)(S[i].length);
        foreach (h; 0 .. 3) {
          counts[h][i] = new int[L[i] + 1];
          foreach (pos; 0 .. L[i] + 1) {
            counts[h][i][pos] = cast(int)(S[i][0 .. pos].count("JOI"[h]));
          }
        }
      }
      
      
      auto J = new int[][](3, N);
      auto JO = new int[][][](2, N);
      auto JOI = new int[][](N);
      foreach (h; 0 .. 3) {
        foreach (i; 0 .. N) {
          J[h][i] = counts[h][i][L[i]];
        }
      }
      foreach (h; 0 .. 2) {
        foreach (i; 0 .. N) {
          JO[h][i] = new int[L[i] + 1];
          JO[h][i][] = -1;
          foreach (pos; 0 .. L[i] + 1) {
            chmax(JO[h][i][counts[h][i][pos]], counts[h + 1][i][L[i]] - counts[h + 1][i][pos]);
          }
        }
      }
      {
        foreach (i; 0 .. N) {
          JOI[i] = new int[L[i] + 1];
          JOI[i][] = -1;
          foreach (pos0; 0 .. L[i] + 1) foreach (pos1; pos0 .. L[i] + 1) {
            if (counts[1][i][pos1] - counts[1][i][pos0] >= K) {
              chmax(JOI[i][counts[0][i][pos0]], counts[2][i][L[i]] - counts[2][i][pos1]);
            }
          }
        }
      }
      
      auto dp = new long[][](3 + 1, K + 1);
      foreach (h; 0 .. 3 + 1) {
        dp[h][] = INF;
      }
      dp[0][0] = 0;
      foreach (h; 0 .. 3) {
        foreach (x; 0 .. K) {
          {
            foreach (i; 0 .. N) {
              const xx = min(x + J[h][i], K);
              chmin(dp[h][xx], dp[h][x] + C[i]);
            }
          }
          if (h < 2) {
            foreach (i; 0 .. N) {
              if (K - x <= L[i] && JO[h][i][K - x] >= 0) {
                const xx = min(JO[h][i][K - x], K);
                chmin(dp[h + 1][xx], dp[h][x] + C[i]);
              }
            }
          }
          if (h < 1) {
            foreach (i; 0 .. N) {
              if (K - x <= L[i] && JOI[i][K - x] >= 0) {
                const xx = min(JOI[i][K - x], K);
                chmin(dp[h + 2][xx], dp[h][x] + C[i]);
              }
            }
          }
        }
        chmin(dp[h + 1][0], dp[h][K]);
      }
      const ans = dp[3][0];
      writeln((ans >= INF) ? -1 : ans);
    }
  } catch (EOFException e) {
  }
}