#include <iostream>
#include <vector>
#include <map>
#include <queue>
#include <limits.h>
#include <set>
#include <algorithm>
using namespace std;
int main()
{
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cout.tie(nullptr);
int n, m;
cin >> n >> m;
vector<vector<bool>> a(n, vector<bool>(m, false));
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
{
char v;
cin >> v;
a[i][j] = v == '#';
}
for (int i = 0; i < n - 1; i++)
for (int j = i + 1; j < n; j++)
{
bool noIntersection = true;
bool equal = true;
for (int k = 0; k < m; k++)
{
if (a[i][k] != a[j][k])
equal = false;
if (a[i][k] && a[j][k])
noIntersection = false;
}
if (!equal && !noIntersection)
{
cout << "No\n";
return 0;
}
}
cout << "Yes\n";
return 0;
}
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