#include <bits/stdc++.h>
using namespace std;
template <class C>
void mini(C& _a4, C _b4) {
  _a4 = min(_a4, _b4);
}
template <class C>
void maxi(C& _a4, C _b4) {
  _a4 = max(_a4, _b4);
}
template <class TH>
void _dbg(const char* sdbg, TH h) {
  cerr << sdbg << '=' << h << endl;
}
template <class TH, class... TA>
void _dbg(const char* sdbg, TH h, TA... a) {
  while (*sdbg != ',') cerr << *sdbg++;
  cerr << '=' << h << ',';
  _dbg(sdbg + 1, a...);
}
template <class T>
ostream& operator<<(ostream& os, vector<T> V) {
  os << "[";
  for (auto& vv : V) os << vv << ",";
  os << "]";
  return os;
}
long long n, l;
long long war[401];
string z[401];
map<string, long long> ma;
long long il = 0;
void add(string x) {
  auto xx = ma.find(x);
  if (xx == ma.end()) {
    (x, il);
    ma[x] = il;
    il++;
  }
}
long long szu(string z) {
  while (1) {
    auto xx = ma.find(z);
    if (xx != ma.end()) {
      return xx->second;
    }
    z = z.substr(1);
  }
}
long long ww[401];
long long t[401][401], pom2[401][401], res[401], pom[401];
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout << fixed << setprecision(11);
  if (0) cout << fixed << setprecision(6);
  cin >> n >> l;
  for (long long i = (0); i <= ((long long)(n)-1); i++) {
    cin >> war[i];
  }
  for (long long i = (0); i <= ((long long)(n)-1); i++) {
    cin >> z[i];
    for (long long j = (0);
         j <= ((long long)(((long long)(z[i]).size()) + 1) - 1); j++) {
      add(z[i].substr(0, j));
    }
  }
  for (long long i = (0); i <= ((long long)(n)-1); i++) {
    for (auto& x : ma) {
      if (((long long)(z[i]).size()) > ((long long)(x.first).size())) continue;
      if (z[i] == x.first.substr(((long long)(x.first).size()) -
                                     ((long long)(z[i]).size()),
                                 ((long long)(z[i]).size())))
        ww[x.second] += war[i];
    }
  }
  for (long long i = (0); i <= ((long long)(il)-1); i++)
    for (long long j = (0); j <= ((long long)(il)-1); j++) t[i][j] = -1e18;
  for (auto& x : ma) {
    for (char k = 'a'; k <= 'z'; k++) {
      string pom = x.first + k;
      long long gd = szu(pom);
      maxi(t[x.second][gd], ww[gd]);
    }
  }
  for (long long i = (0); i <= ((long long)(il)-1); i++) res[i] = -1e18;
  res[0] = 0;
  while (l) {
    if (l & 1) {
      for (long long i = (0); i <= ((long long)(il)-1); i++) pom[i] = -1e18;
      for (long long i = (0); i <= ((long long)(il)-1); i++)
        for (long long j = (0); j <= ((long long)(il)-1); j++)
          maxi(pom[j], res[i] + t[i][j]);
      for (long long i = (0); i <= ((long long)(il)-1); i++) res[i] = pom[i];
    }
    l /= 2;
    for (long long i = (0); i <= ((long long)(il)-1); i++)
      for (long long j = (0); j <= ((long long)(il)-1); j++) pom2[i][j] = -1e18;
    for (long long i = (0); i <= ((long long)(il)-1); i++)
      for (long long j = (0); j <= ((long long)(il)-1); j++)
        for (long long k = (0); k <= ((long long)(il)-1); k++)
          maxi(pom2[i][k], t[i][j] + t[j][k]);
    for (long long i = (0); i <= ((long long)(il)-1); i++)
      for (long long j = (0); j <= ((long long)(il)-1); j++)
        t[i][j] = pom2[i][j];
  }
  long long out = 0;
  for (long long i = (0); i <= ((long long)(il)-1); i++) maxi(out, res[i]);
  cout << out << "\n";
}
