#include <bits/stdc++.h>
using namespace std;
using ll=long long;
int main(){
	int h,w;
	cin>>h>>w;
	vector<string> s(h);
	for(int i=0;i<h;i++)cin>>s[i];
	vector<vector<bool>> a(h,vector<bool>(w)),b(h,vector<bool>(w));
	a[0][0]=true;
	b[h-1][w-1]=true;
	for(int i=0;i<h;i++)for(int j=0;j<w;j++){
		if(a[i][j]){
			if(i<h-1&&s[i+1][j]!='#')a[i+1][j]=true;
			if(j<w-1&&s[i][j+1]!='#')a[i][j+1]=true;
		}
	}
	for(int i=h-1;i>=0;i--)for(int j=w-1;j>=0;j--){
		if(b[i][j]){
			if(i>0&&s[i-1][j]!='#')b[i-1][j]=true;
			if(j>0&&s[i][j-1]!='#')b[i][j-1]=true;
		}
	}
	if(a[h-1][w-1]){
		cout<<h+w-2<<endl;
		return 0;
	}
	vector<int> ca(h,w),ra(w,h),cb(h,-1),rb(w,-1);
	for(int i=0;i<h;i++)for(int j=0;j<w;j++){
		if(a[i][j]){
			ca[i]=min(ca[i],j);
			ra[j]=min(ra[j],i);
		}
		if(b[i][j]){
			cb[i]=max(cb[i],j);
			rb[j]=max(rb[j],i);
		}
	}
	for(int i=0;i<h;i++){
		if(ca[i]<=cb[i]){
			cout<<h+w-1<<endl;
			return 0;
		}
	}
	for(int j=0;j<w;j++){
		if(ra[j]<=rb[j]){
			cout<<h+w-1<<endl;
			return 0;
		}
	}
	cout<<h+w<<endl;
}