#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T sqr(T x) {
  return x * x;
}
template <class T>
inline string tostr(const T &x) {
  stringstream ss;
  ss << x;
  return ss.str();
}
inline long long parse(const string &s) {
  stringstream ss(s);
  long long x;
  ss >> x;
  return x;
}
const double EPS = 1e-12;
const int INF = 1000 * 1000 * 1000;
const long long LINF = INF * 1ll * INF;
const double DINF = 1e200;
const double PI = 3.1415926535897932384626433832795l;
int gcd(int a, int b) { return a ? gcd(b % a, a) : b; }
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long gcdex(long long a, long long b, long long &x, long long &y) {
  if (!a) {
    x = 0, y = 1;
    return b;
  }
  long long k = b / a;
  long long g = gcdex(b - k * a, a, y, x);
  x -= k * y;
  return g;
}
long long inv(long long a, long long m) {
  long long x, y, g;
  g = gcdex(a, m, x, y);
  return (x % (m / g) + m / g) % m / g;
}
long long crt(long long a1, long long m1, long long a2, long long m2) {
  long long a = (a2 - a1 % m2 + m2) % m2;
  long long x, y, g;
  g = gcdex(m1, m2, x, y);
  if (a % g) return -1;
  long long m = m1 / g * m2;
  x *= a / g;
  x = (x % m2 + m2) % m2;
  long long r = (a1 + x * m1) % m;
  assert(r % m1 == a1 && r % m2 == a2);
  return r;
}
long long powmod(long long a, long long p, long long m) {
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
bool isprime(long long a) {
  if (a <= 1) return false;
  for (long long i = 2; i * i <= a; ++i) {
    if (a % i == 0) return false;
  }
  return true;
}
long long sqrtup(long long a) {
  if (!a) return 0;
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x >= a) --x;
  while ((x + 1) * (x + 1) < a) ++x;
  return x + 1;
}
long long isqrt(long long a) {
  long long x = max(0ll, (long long)sqrt((double)a));
  while (x * x > a) --x;
  while ((x + 1) * (x + 1) <= a) ++x;
  return x;
}
long long sgn(long long x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v);
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p);
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m);
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a);
template <class T>
ostream &operator<<(ostream &s, const vector<T> &v) {
  s << '[';
  for (int i = 0; i < (((int)(v).size())); ++i) {
    if (i) s << ',';
    s << v[i];
  }
  s << ']';
  return s;
}
template <class A, class B>
ostream &operator<<(ostream &s, const pair<A, B> &p) {
  s << "(" << p.first << "," << p.second << ")";
  return s;
}
template <class K, class V>
ostream &operator<<(ostream &s, const map<K, V> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it.first << ": " << it.second;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const set<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T>
ostream &operator<<(ostream &s, const multiset<T> &m) {
  s << "{";
  bool f = false;
  for (const auto &it : m) {
    if (f) s << ",";
    f = true;
    s << it;
  }
  s << "}";
  return s;
}
template <class T, size_t N>
ostream &operator<<(ostream &s, const array<T, N> &a) {
  s << '[';
  for (int i = 0; i < (((int)(a).size())); ++i) {
    if (i) s << ',';
    s << a[i];
  }
  s << ']';
  return s;
}
template <size_t n, class... T>
struct put1 {
  static ostream &put(ostream &s, const tuple<T...> &t) {
    s << get<sizeof...(T) - n>(t);
    if (n > 1) s << ',';
    return put1<n - 1, T...>::put(s, t);
  }
};
template <class... T>
struct put1<0, T...> {
  static ostream &put(ostream &s, const tuple<T...> &t) { return s; }
};
template <class... T>
ostream &operator<<(ostream &s, const tuple<T...> &t) {
  s << "(";
  put1<sizeof...(T), T...>::put(s, t);
  s << ")";
  return s;
}
ostream &put2(ostream &s, const tuple<> &t) { return s; }
template <class U>
ostream &put2(ostream &s, const tuple<U> &t) {
  return s << get<0>(t);
}
template <class U, class V, class... T>
ostream &put2(ostream &s, const tuple<U, V, T...> &t) {
  return s << t;
}
vector<string> P;
map<string, int> I;
vector<long long> C;
struct mat {
  vector<vector<long long>> a;
  mat(int n) : a(n, vector<long long>(n, -LINF)) {
    for (int i = 0; i < (n); ++i) a[i][i] = 0;
  }
  mat operator*(const mat &b) const {
    mat r(((int)(a).size()));
    for (int i = 0; i < (((int)(a).size())); ++i) {
      for (int j = 0; j < (((int)(a).size())); ++j) {
        r.a[i][j] = -LINF;
        for (int k = 0; k < (((int)(a).size())); ++k) {
          long long t1 = a[i][k];
          long long t2 = b.a[k][j];
          if (t1 < 0 || t2 < 0) continue;
          r.a[i][j] = max(r.a[i][j], t1 + t2);
        }
      }
    }
    return r;
  }
};
mat pw(mat a, long long p) {
  mat r(((int)(a.a).size()));
  while (p) {
    if (p & 1) r = r * a;
    p >>= 1;
    a = a * a;
  }
  return r;
}
void gen() {
  int n = 1, k = 200;
  long long l = LINF / 10000;
  cout << n << ' ' << l << endl;
  for (int i = 0; i < (n); ++i) cout << rand() % 100 + 1 << ' ';
  cout << endl;
  for (int i = 0; i < (n); ++i) {
    for (int j = 0; j < (k); ++j) cout << (char)('a' + rand() % 26);
    cout << endl;
  }
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
  if (argc > 1) {
    gen();
    return 0;
  }
  int n;
  long long l;
  cin >> n >> l;
  vector<long long> A(n);
  for (int i = 0; i < (n); ++i) cin >> A[i];
  map<string, long long> M;
  for (int i = 0; i < (n); ++i) {
    string s;
    cin >> s;
    M[s] += A[i];
    for (int k = 0; k < (((int)(s).size()) + 1); ++k) {
      string p = s.substr(0, k);
      if (I.count(p)) continue;
      I[p] = ((int)(P).size());
      P.push_back(p);
    }
  }
  C.resize(((int)(P).size()));
  for (int i = 0; i < (((int)(P).size())); ++i) {
    string p = P[i];
    for (int k = 0; k < (((int)(p).size()) + 1); ++k) {
      string s = p.substr(k);
      auto it = M.find(s);
      if (it != M.end()) C[i] += it->second;
    }
  }
  mat m(((int)(P).size()));
  for (int i = 0; i < (((int)(P).size())); ++i) {
    m.a[i][i] = -LINF;
    for (char c = 'a'; c <= 'z'; ++c) {
      string s = P[i] + c;
      bool f = false;
      for (int k = 0; k < (((int)(s).size()) + 1); ++k) {
        string t = s.substr(k);
        auto it = I.find(t);
        if (it == I.end()) continue;
        int j = it->second;
        m.a[i][j] = max(m.a[i][j], C[j]);
        f = true;
        break;
      }
      assert(f);
    }
  }
  m = pw(m, l);
  long long r = -LINF;
  for (int i = 0; i < (((int)(P).size())); ++i) {
    r = max(r, m.a[I[""]][i]);
  }
  assert(r >= 0);
  cout << r;
  return 0;
}
