/*
Author : N_o_o_B
Created : March 21 2020 17:27:45 
*/
#include <bits/stdc++.h>
using namespace std;
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
*/
#define TRACE
#ifdef TRACE
#define trace(...) { cerr<<"[ "; __trace__(#__VA_ARGS__, __VA_ARGS__);}
#undef endl
template <typename Arg1,typename Arg2>
ostream& operator << (ostream& out, const pair<Arg1,Arg2> &x) {
    return out<<"("<<x.first<<","<<x.second<<")";
}
 
template <typename Arg1>
ostream& operator << (ostream& out, const vector<Arg1> &a) {
    out<<"[";for(const auto &x:a)out<<x<<",";return out<<"]";
}
 
template <typename Arg1>
ostream& operator << (ostream& out, const set<Arg1> &a) {
    out<<"[";for(const auto &x:a)out<<x<<",";return out<<"]";
}
 
template <typename Arg1,typename Arg2>
ostream& operator << (ostream& out, const map<Arg1,Arg2> &a) {
    out<<"[";for(const auto &x:a)out<<x<<",";return out<<"]";
}
 
template <typename Arg1>
void __trace__(const string name, Arg1&& arg1){
    cerr << name << " : " << arg1 << " ] " << endl;
}
 
template <typename Arg1, typename... Args>
void __trace__(const string names, Arg1&& arg1, Args&&... args){
    const string name = names.substr(0,names.find(','));
    cerr<<name<<" : "<<arg1<<" | ";
    __trace__(names.substr(1+(int)name.size()), args...);
}
#else
    #define trace(args...)
#endif
 
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pair<int,int>> vii;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<pair<ll,ll>> vll;
typedef vector<vl> vvl;
//typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> oset;
#define fori(i,n) for(int i=0;i<n;i++)
#define rep(i,a,b) for(int i=a;i<=b;i++)
#define repd(i,a,b) for(int i=a;i>=b;i--)
#define ford(i,n)  for(int i=n-1;i>=0;i--)
#define trav(x,a) for(auto& x:a)
#define all(x) x.begin(),x.end()
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define fi first
#define se second
clock_t time_p=clock();
void time_taken()
{
    time_p=clock()-time_p;
    cerr<<"Time Taken : "<<(float)(time_p)/CLOCKS_PER_SEC<<"\n";
}
//const ll mod=998244353;
const ll mod=1e9+7;
const ll INF=1e18;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    cout.precision(12);cout << fixed;

    int n,m;
    cin >> n >> m;
    vector<string> a(n);
    fori(i,n) cin >> a[i];
    vvi dp(n,vi(m,mod));
    ford(i,n){
        ford(j,m){
            if(a[i][j] == '#'){
                queue<pii> q;
                q.push({i,j});
                int dx[2] = {+1,0};
                int dy[2] = {0,+1};
                vector<vector<bool>> vis(n,vector<bool>(m));
                vis[i][j] = 1;
                while(q.size()){
                    int x = q.front().fi;
                    int y = q.front().se;
                    if(x==n-1 and y==m-1){
                        dp[i][j] = 1;
                        break;
                    }
                    q.pop();
                    fori(ii,2){
                        int tox = x + dx[ii];
                        int toy = y + dy[ii];
                        if(tox < n and toy < m ){
                            if(vis[tox][toy] == 0 and a[tox][toy] == '#'){
                                vis[tox][toy] = 1;
                                q.push({tox,toy});
                            }
                            else if(a[tox][toy] == '.'){
                                dp[i][j] = min(dp[i][j],dp[tox][toy] + 1);
                            }
                        }
                    }
                }
            }
            else{
                if(i == n-1 and j == m-1){
                    dp[i][j] = 0;
                }
                else if(i == n-1){
                    dp[i][j] = dp[i][j+1];
                }
                else if(j == m-1){
                    dp[i][j] = dp[i+1][j];
                }
                else{
                    dp[i][j] = min(dp[i+1][j],dp[i][j+1]);
                }
            }
        }
    }
    // trace(dp);

    cout << dp[0][0] << endl;

    time_taken();
    return 0;
}

Measured memory_bytes: 512