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#include <bits/stdc++.h>
#define ll long long int
#define P pair
#define F first
#define S second
#define p_b push_back
#define ld long double
#define N 5000005
//#include <wadim>
ll mod = 1000000000 + 7; //4294967296; 1000000000 + 7; 998244353; 2*3*5*7*11*13*17*19*23 + 1
ll inf = 1000000000000000000;
using namespace std;

mt19937 unlucko(chrono::steady_clock::now().time_since_epoch().count());

//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//using ordered_set_pair = tree<pair<ll, ll>, null_type, less<pair<ll, ll> >, rb_tree_tag, tree_order_statistics_node_update>;
//using ordered_set=tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>;

int main()
{
    iostream::sync_with_stdio(false);
    cin.tie(0);
    int n, m; cin >> n >> m;
    bool ok = true;
    int a[m]{};
    for(int i=0;i<n;i++){
        vector<int> b;
        for(int j=0;j<m;j++){
            char x; cin >> x;
            if(x == '#')
                b.push_back(j);
        }
        if(b.empty())
            continue;
        for(auto it:b)
            a[it] ++;
        for(auto it:b){
            if(a[it] != a[b[0]])
                ok = false;
        }
    }
    if(ok)
        cout << "Yes\n";
    else
        cout << "No\n";
}
