// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>


using namespace std;


#define ll long long
#define flt double
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()


mt19937 rnd(234);
const ll inf = 1e18;


const ll mod = 1e9+7;


ll bin_pow(ll x, ll n){
    if(n == 0){
        return 1;
    }
    ll a = bin_pow(x, n / 2);
    a = (a * a) % mod;
    if(n & 1){
        a = (a * x) % mod;
    }
    return a;
}



ll rev(ll x){
    return bin_pow(x, mod - 2);
}


vector<ll> f, rvf;

void build_f(int n){
    f.resize(n + 1);
    rvf.resize(n + 1);
    f[0] = rvf[0] = 1;
    for(int i = 1; i <= n; i += 1){
        f[i] = (f[i - 1] * i) % mod;
        rvf[i] = rev(f[i]);
    }
}


ll cnk(ll n, ll k){
    return f[n] * rvf[k] % mod * rvf[n - k] % mod;
}


int n, m;
vector<vector<int>> a;
vector<int> cnt;
vector<int> dp;


int32_t main(){
    if(1){
        ios::sync_with_stdio(0);
        cin.tie(0);
        cout.tie(0);
    }
    cin >> n >> m;
    build_f(n);
    a.assign(m, vector<int>(n));
    for(int i = 0; i < m; i += 1){
        for(int j = 0; j < n; j += 1){
            char c;
            cin >> c;
            a[i][j] = (c == 'H');
        }
    }
    cnt.assign(1 << m, 0);
    for(int i = 0; i < n; i += 1){
        ll mask = 0;
        for(int j = 0; j < m; j += 1){
            if(a[j][i]){
                mask += 1 << j;
            }
        }
        cnt[mask] += 1;
    }
    dp.assign(1 << m, 0);
    ll rs = 0;
    for(ll mask = 0; mask < (1 << m); mask += 1){
        if(cnt[mask] >= 1){
            ll t = cnt[mask];
            ll bebra = 0;
            for(int k = 1; k <= t; k += 1){
                bebra = (bebra + cnk(t, k) * f[k] % mod) % mod;
            }
            ll aboba = 0;
            for(int sub_mask = ((mask - 1) & mask); true; sub_mask = ((sub_mask - 1) & mask)){
                aboba = (aboba + dp[sub_mask]) % mod;
                if(sub_mask == 0){
                    break;
                }
            }
            dp[mask] = (aboba + 1) * bebra % mod;
            rs = (rs + dp[mask]) % mod;
        }
    }
    cout << rs << "\n";
    return 0;
}