#include <bits/stdc++.h>
using namespace std;
pair<int,int> par[2005];
string s[1005];
pair<int,int> find(pair<int,int> x)
{
if (par[x.first]==x)
return x;
auto p=find(par[x.first]);
p.second^=par[x.first].second;
return par[x.first]=p;
}
int Union(int x,int y,int a)
{
auto xx=find({x,0}),yy=find({y,0});
if (xx.first==yy.first)
return ((xx.second^yy.second)!=a);
par[xx.first]={yy.first,(a^xx.second^yy.second)};
return 0;
}
int main()
{
int n,k;
cin >> n >> k;
for (int i=0;i<2*n;i++)
par[i]={i,0};
for (int i=0;i<n;i++)
{
cin >> s[i];
for (int j=0;j<n;j++)
k-=Union(i,j+n,s[i][j]=='o');
}
printf(k>=0? "DA":"NE");
}
