#include<stdio.h>
#include<string.h>
#include<iostream>
#include<map>
#define M 100005
#define P 1000000007
using namespace std;
map<int,int>mp;
int fact[M],dp[2000][2000],A[M],C[M];
bool check(int x){
    if(x==0)return false;
    while(x){
        int d=x%10;
        if(d!=4&&d!=7)return false;
        x/=10;
    }
    return true;
}
int fast(int a,int b){
    int res=1;
    while(b){
        if(b&1)res=1LL*res*a%P;
        b>>=1;
        a=1LL*a*a%P;
    }
    return res;
}
int Calc(int n,int m){
    if(n>m)return 0;
    return 1LL*fact[m]*fast(fact[m-n],P-2)%P*fast(fact[n],P-2)%P;
}
void Check(int &a,int b){
    a+=b;
    if(a>P)a%=P;
}
int main(){
//  freopen("lucky.in","r",stdin);
//  freopen("lucky.out","w",stdout);
    int n,k,tot=0,ans=0,d=0;
    scanf("%d %d",&n,&k);
    for(int i=1;i<=n;i++){
        scanf("%d",&A[i]);
        if(check(A[i]))mp[A[i]]++;
        else d++;
    }
    fact[0]=1;
    for(int i=1;i<=n;i++)
        fact[i]=1LL*fact[i-1]*i%P;
    for(map<int,int>::iterator it=mp.begin();it!=mp.end();it++)
        C[++tot]=it->second;
    for(int i=0;i<=tot;i++)
        dp[i][0]=1;
    for(int i=1;i<=tot;i++)
        for(int j=1;j<=i;j++){
            Check(dp[i][j],dp[i-1][j]);
            Check(dp[i][j],1LL*dp[i-1][j-1]*C[i]%P);
        }
    for(int i=0;i<=min(tot,k);i++)
        ans=(ans+1LL*dp[tot][i]*Calc(k-i,d))%P;
    printf("%d\n",ans);
    return 0;
}