#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chkmin(T &x, T y) {
  return y < x ? x = y, 1 : 0;
}
template <class T>
inline bool chkmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
inline long long Max(long long x, long long y) { return x > y ? x : y; }
inline long long Min(long long x, long long y) { return x < y ? x : y; }
int n, m;
int res;
map<int, int> lck;
map<int, int>::iterator it;
long long fac[100002], inv[100002];
long long dp[100002];
void Add(long long &x, long long y) {
  x += y;
  if (x >= 1000000007)
    x -= 1000000007;
  else if (x < 0)
    x += 1000000007;
}
bool check(int x) {
  while (x) {
    if (x % 10 != 4 && x % 10 != 7) return 0;
    x /= 10;
  }
  return 1;
}
void Init() {
  fac[0] = fac[1] = 1;
  inv[0] = inv[1] = 1;
  for (int i = (2), i_end_ = (100002); i < i_end_; i++)
    fac[i] = fac[i - 1] * i % 1000000007;
  for (int i = (2), i_end_ = (100002); i < i_end_; i++)
    inv[i] = (1000000007 - (1000000007 / i)) * inv[1000000007 % i] % 1000000007;
  for (int i = (2), i_end_ = (100002); i < i_end_; i++)
    inv[i] = inv[i] * inv[i - 1] % 1000000007;
}
long long C(int n, int m) {
  if (n < 0 || m > n) return 0;
  return fac[n] * inv[m] % 1000000007 * inv[n - m] % 1000000007;
}
int main() {
  Init();
  scanf("%d%d", &n, &m);
  for (int i = (1), i_end_ = (n); i <= i_end_; i++) {
    int x;
    scanf("%d", &x);
    if (check(x))
      lck[x]++;
    else
      res++;
  }
  int tot = 0;
  dp[0] = 1;
  for (it = lck.begin(); it != lck.end(); it++) {
    tot++;
    for (int i = (min(tot, m)), i_end_ = (1); i >= i_end_; i--)
      Add(dp[i], dp[i - 1] * it->second % 1000000007);
  }
  long long ans = 0;
  for (int i = (0), i_end_ = (min(tot, m)); i <= i_end_; i++)
    Add(ans, dp[i] * C(res, m - i) % 1000000007);
  printf("%I64d\n", ans);
  return 0;
}
