#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const double eps = 1e-12;
const int inf = 2000000000;
const long long int infLL = (long long int)1e18;
long long int MOD = 1000000007;
int MOD1 = 1000000007;
int MOD2 = 1000000009;
inline bool checkBit(long long int n, long long int i) {
  return n & (1LL << i);
}
inline long long int setBit(long long int n, long long int i) {
  return n | (1LL << i);
  ;
}
inline long long int resetBit(long long int n, long long int i) {
  return n & (~(1LL << i));
}
int dx[] = {0, 0, +1, -1};
int dy[] = {+1, -1, 0, 0};
inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }
inline bool isLeapYear(long long int year) {
  return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
inline void normal(long long int &a) {
  a %= MOD;
  (a < 0) && (a += MOD);
}
inline long long int modMul(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a * b) % MOD;
}
inline long long int modAdd(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a + b) % MOD;
}
inline long long int modSub(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  a -= b;
  normal(a);
  return a;
}
inline long long int modPow(long long int b, long long int p) {
  long long int r = 1LL;
  while (p) {
    if (p & 1) r = modMul(r, b);
    b = modMul(b, b);
    p >>= 1LL;
  }
  return r;
}
inline long long int modDiv(long long int a, long long int b) {
  return modMul(a, modPow(b, MOD - 2));
}
bool comp(const pair<long long int, pair<long long int, long long int> > &p1,
          const pair<long long int, pair<long long int, long long int> > &p2) {
  return p1.first > p2.first;
}
bool comp1(const pair<long long int, long long int> &p1,
           const pair<long long int, long long int> &p2) {
  if (p1.first == p2.first) {
    return p1.second > p2.second;
  }
  return p1.first < p2.first;
}
long long int converter(string a) {
  long long int i, mul = 1LL, r, t, ans = 0LL;
  if (a.length() == 0) return 0;
  for (i = a.length() - 1; i >= 0; i--) {
    t = a[i] - '0';
    r = t % 10;
    ans += (mul * r);
    mul = mul * 10;
  }
  return ans;
}
int msb(unsigned x) {
  union {
    double a;
    int b[2];
  };
  a = x;
  return (b[1] >> 20) - 1023;
}
const int MAX = 100005;
long long int n, a[MAX], k;
long long int dp[1030][1030], fact[MAX];
vector<long long int> store;
map<long long, int> lucky, cnt;
void genLucky(long long int idx, long long int num) {
  lucky[num] = 1;
  if (idx == 9) return;
  genLucky(idx + 1, (num * 10) + 4);
  genLucky(idx + 1, (num * 10) + 7);
}
long long int solve(int idx, int used) {
  if (idx == store.size()) {
    if (used == 0)
      return 1;
    else
      return 0;
  }
  if (dp[idx][used] != -1) return dp[idx][used];
  long long int ret = 0;
  if (used > 0) {
    ret += (cnt[store[idx]] * solve(idx + 1, used - 1));
  }
  ret += solve(idx + 1, used);
  return dp[idx][used] = ret % MOD;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  cout.unsetf(ios::floatfield);
  cout.precision(20);
  cout.setf(ios::fixed, ios::floatfield);
  ;
  genLucky(0, 0);
  fact[0] = 1;
  long long int i, uncnt = 0;
  cin >> n >> k;
  for (i = 1; i <= n; ++i) {
    cin >> a[i];
    if (lucky[a[i]] == 1) {
      cnt[a[i]]++;
      if (cnt[a[i]] == 1) store.push_back(a[i]);
    } else
      uncnt++;
    fact[i] = (fact[i - 1] * i) % MOD;
  }
  memset(dp, -1, sizeof(dp));
  long long int ans = 0;
  for (i = 0; i <= min(k, (long long int)store.size()); ++i) {
    long long int need = k - i;
    if (need > uncnt) continue;
    long long int cur = (fact[need] * fact[uncnt - need]) % MOD;
    cur = modDiv(fact[uncnt], cur);
    ans += (cur * (solve(0, i)));
    ans %= MOD;
  }
  cout << ans << '\n';
  return 0;
}
