#include <iostream>
#include <cstdio>
#include <iomanip>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <bitset>
#include <stack>
#include <utility>
#include <numeric>
#include <algorithm>
#include <functional>
#include <cctype>
#include <complex>
#include <string>
#include <sstream>
#include <fstream>
#include <cassert>
using namespace std;

//common

typedef int  i32;
typedef long long i64,ll;
typedef long double ld;

#define BR "\n"
#define ALL(c) (c).begin(),(c).end()
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define FOR(i,l,r) for(int i=(int)l;i<(int)(r);++i)
#define EACH(it,o) for(auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l,v,r) ((l)<=(v) && (v)<(r))

//config
//#define NDEBUG
//#define INF 1<<30
//#define EPS 1e-8
//const ll MOD =100000007;

//debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp,act)
#define STOP(e)
#else
#define DUMP(x)  cerr << #x << " = " << (x)
#define DUMPLN(x)  DUMP(x) <<endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x)<<endl
#define LINE()    cerr<< " (L" << __LINE__ << ")"
#define LINELN()    LINE()<<endl
#define CHECK(exp,act)  if(exp!=act){DUMPLN(exp);DEBUGLN(act);}
#define STOP(e)  CHECK(e,true);if(!(e)) exit(1);
#endif

template<class T> inline string toString(const vector<T>& x) {
	stringstream ss;
	REP(i,x.size()){
		if(i!=0)ss<<" ";
		ss<< x[i];
	}
	return ss.str();
}

template<class T> inline string toString(const vector<vector<T> >& map) {
	stringstream ss;
	REP(i,map.size()){
		if(i!=0)ss<<BR;
		ss<< toString(map[i]);
	}
	return ss.str();
}
template<class K,class V>  string toString(map<K,V>& x) {
	string res;stringstream ss;
	for(auto& p:x)ss<< p.first<<":" << p.second<<" ";
	return ss.str();
}

string BITtoString(int bit){
    stringstream ss;
    while(bit!=0){ss<<(bit%2);bit/=2;}
    string res=ss.str();reverse(ALL(res));
    return res;
}

template<typename T,typename V> inline T pmod(T v,V MOD){
	return (v%MOD+MOD)%MOD;
}
#define nextInt(n) scanf("%d",&n)
#define defInt(n) int n;nextInt(n)
#define nextLong(n) scanf("%lld",&n)
#define defLong(n) ll n;nextLong(n)
#define nextDouble(n) scanf("%lf",&n)



namespace MaximamFlows{
	typedef int Flow;
    const int INF = 1 << 28;
    struct Edge{
        int to;Flow cap;int rev;
        Edge(int to,Flow cap,int rev) : to(to),cap(cap),rev(rev) {};
    };
    typedef vector<vector<Edge> > Graph;

    //dinic O(V^2*E)
    class MaximamFlow{
    private:
            //iter　次に調べる時の開始位置 距離
        vector<int> iter,dist;
            //sからのbfs距離の計算
        void bfs_dist(int s){
            fill(ALL(dist),-1);dist[s]=0;
            queue<int> que;que.push(s);
            while(!que.empty()){
                int v=que.front();que.pop();
                EACH(e,G[v]){
                    if(e->cap>0 && dist[e->to] == -1){
                        dist[e->to]=dist[v]+1;
                        que.push(e->to);
                    }
                }
            }
        }
            //増加パス
        Flow dfs_best_path(int v,int t,Flow f){
            if(v==t)return f;
            for(int &i =iter[v];i<(int)G[v].size();i++){
                Edge& e=G[v][i];
                if(e.cap>0 && dist[v]<dist[e.to]){
                    Flow d=dfs_best_path(e.to,t,min(f,e.cap));
                    if(d>0){
                        e.cap-=d;G[e.to][e.rev].cap+=d;
                        return d;
                    }
                }
            }
            return 0;
        }
    public:
        int V;Graph G;
        MaximamFlow(int V):V(V){
            G=Graph(V);
            dist=vector<int>(V);iter=vector<int>(V);
        }

        void add_edge(int from,int to,int cap){
            int fromrev=G[to].size(),torev=G[from].size();
            G[from].push_back(Edge(to,cap,fromrev));G[to].push_back(Edge(from,0,torev));
        }
        int max_flow(int s,int t){
            Flow flow=0;
            while(true){
                bfs_dist(s);
                if(dist[t]<0)return flow;
                fill(ALL(iter),0);
                Flow f;
                while((f=dfs_best_path(s,t,INF))>0)flow+=f;
            }return -1;
        }
    };
}
using namespace MaximamFlows;


class Main{
	public:

	void run(){
		// ifstream cin("D2");
	    //		ofstream cout( "D2.out" );
		while(true){
			int H,W;cin >> H >> W;if(H==0 && W==0)break;
			vector<string> board(H);
			REP(y,H)cin >> board[y];

			vector<vector<bool>> cboard(H-1,vector<bool>(W-1));
			vector<pair<int,int>> cs;
			REP(y,H-1)REP(x,W-1){
				int sz=0;
				if(board[y][x]=='#')sz++;
				if(board[y+1][x]=='#')sz++;
				if(board[y][x+1]=='#')sz++;
				if(board[y+1][x+1]=='#')sz++;
				if(sz==3){
					cboard[y][x]=true;
					cs.push_back(make_pair(y,x));
				}
			}
			int C=cs.size();
			//２つの隅を通る辺の列挙
			vector<pair<pair<int,int>,pair<int,int>>> es;
			REP(i,C)REP(j,C)if(i<j){
			  if(cs[i].first==cs[j].first){//y eq
			  	int y=cs[i].first;
			  	bool ok=true;
			  	for(int x=min(cs[i].second,cs[j].second)+1;x<=max(cs[i].second,cs[j].second);x++){
			  		if(board[y][x]!='#' ||board[y+1][x]!='#'){
			  			ok=false;
			  		}
			  	}
			  	if(ok)es.push_back(make_pair(cs[i],cs[j]));
			  }
			  if(cs[i].second==cs[j].second){//x eq
			  	int x=cs[i].second;
			  	bool ok=true;
			  	for(int y=min(cs[i].first,cs[j].first)+1;y<=max(cs[i].first,cs[j].first);y++){
			  		if(board[y][x]!='#' ||board[y][x+1]!='#'){
			  	//	 	DUMP(i);DUMP(j);DUMP(BR);
			  			ok=false;
			  		}
			  	}
			  	if(ok)es.push_back(make_pair(cs[i],cs[j]));
			  }
			}
			
			int N=es.size();
			Graph g(N);
			//辺がぶつかる場合に枝をはる．
			REP(i,N)REP(j,N)if(i<j){
				int y1=es[i].first.first,x1=es[i].first.second;
				int y2=es[i].second.first,x2=es[i].second.second;
				int y3=es[j].first.first,x3=es[j].first.second;
				int y4=es[j].second.first,x4=es[j].second.second;

				bool hit=false;
				if(y1==y2 && x3==x4){
					if(min(x1,x2)<=x3 && x3<=max(x1,x2) && min(y3,y4)<=y1 && y1<=max(y3,y4))
						hit=true;
				}else if(x1==x2 && y3==y4){
					if(min(x3,x4)<=x1 && x1<=max(x3,x4) && min(y1,y2)<=y3 && y3<=max(y1,y2))
						hit=true;
				}
				if(hit){
					g[i].push_back(Edge(j,-1,-1));g[j].push_back(Edge(i,-1,-1));
				}
			}

			//2部グラフカラーリング
			colors=vector<int>(N,-1);
			REP(i,N)dfs(g,i,0);

			//2部グラフマッチング
			MaximamFlow mf(N+2);
			REP(i,N)EACH(e,g[i])if(i<e->to){
				if(colors[i]==0) mf.add_edge(i,e->to,1);
				if(colors[i]==1) mf.add_edge(e->to,i,1);
			}
			REP(i,N){
				if(colors[i]==0)mf.add_edge(N,i,1);
				if(colors[i]==1)mf.add_edge(i,N+1,1);
			}

			//最大独立集合
			int D=N-mf.max_flow(N,N+1);
			
			cout << (C-D+1)<<endl;
		}
	}

	vector<int> colors;
	void dfs(Graph& g,int v,int c){
		if(colors[v]!=-1)return;
		colors[v]=c;
		EACH(e,g[v]){
			dfs(g,e->to,1-c);
		}
	}
};
int main(){
	cout <<fixed<<setprecision(15);	
	ios::sync_with_stdio(false);
	Main().run();
	return 0;
}

Measured memory_bytes: 2160