// Marcin Knapik
#include<bits/stdc++.h>
// #pragma GCC optimize("O3")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
using namespace std;

// #include <ext/pb_ds/assoc_container.hpp> // order_of_key
// #include <ext/pb_ds/tree_policy.hpp> // find by order
// using namespace __gnu_pbds; 
// #define ordered_set tree< int , null_type,less< int >, rb_tree_tag,tree_order_statistics_node_update>  

// const ll MAX_LL = 0xFFFFFFFFFFFFFFFF;
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// #define losuj(a, b) uniform_int_distribution<ull>(a, b)(rng)

typedef long double             ld;
typedef long long               ll;
typedef unsigned long long      ull;
typedef pair<ll, ll>            pll;
typedef pair<int, int>          ii;
typedef vector<int>             vi;
typedef vector<ii>              vii;
typedef vector<vi>              vvi;
typedef vector<vector<ii>>      vvii;
typedef vector< ll >            vll;
typedef vector< pll >           vpll;

#define boost                   ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define sz(a)                   (int)(a).size()
#define pb                      push_back
#define all(c)                  (c).begin(), (c).end()
#define rall(c)                 (c).rbegin(), (c).rend()
#define FOR(i, a)               for (int i = 0; i < (a); i++)
#define f                       first
#define s                       second

template <class T> inline bool setmin(T &a, T b){if (a > b)return a = b, 1;return 0;}
template <class T> inline bool setmax(T &a, T b){if (a < b)return a = b, 1;return 0;}

template<class T> inline T fast(T a,T b,T mod) {ll res = 1; while(b){if(b&1) res = (res*a)%mod;a = (a*a)%mod;b >>= 1;}return res;}
template<class T> inline T russian(T a, T b, T mod) {ll res = 0; while(b){if(b&1) res = (res + a)%mod; a = (a+a)%mod; b>>=1;}return res;}
template<class T> istream &operator>>(istream &os, vector<T> &container){for (auto &u : container)os >> u;return os;}
template<class T> ostream &operator<<(ostream &os, const vector<T> &container){for (auto &u : container)os << u << " ";return os;}
template<class T> inline T gcd(T a, T b) { while (b)swap(a %= b, b); return a; }

const ll INF = 1e9 + 7;
const ll mod = 1186782211;
// const ll BIG_INF = 1000000000000000000;
const ll BIG_INF = 15000000000000;
const ll N = 1e6+7;
const ll T = 1<<20;
const ll Hope = 1000000123;

ll n, m, k, q;

char tab[1002][222];
int ans[105][105];
bool odw[105][105];

int X[] = {1, 0};
int Y[] = {0, 1};

int main(){
	boost;

	cin >> n >> m;

	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= m; j++){
			cin >> tab[i][j];
			ans[i][j] = INF;
		}
	}
	deque<ii> kol;
	kol.push_front({1, 1});
	ans[1][1] = 0;

	while(sz(kol)){
		auto v = kol.front();
		int x = v.f;
		int y = v.s;

		kol.pop_front();
		if(odw[x][y])
			continue;
		odw[x][y] = 1;

		if(x == n and y == m){
			cout << ans[x][y] + (tab[1][1] == '#')<< '\n';
			exit(0);
		}

		FOR(i, 2){
			int nx = x + X[i];
			int ny = y + Y[i];

			if(!odw[nx][ny]){
				if(tab[x][y] == tab[nx][ny] || (tab[x][y] == '#' and tab[nx][ny] == '.')){
					kol.push_front({nx, ny});
					ans[nx][ny] = ans[x][y];
				}
				if(tab[x][y] == '.' and tab[nx][ny] == '#'){
					kol.push_back({nx, ny});
					setmin(ans[nx][ny], ans[x][y] + 1);
				}
			}
		}
	}
	exit(0);
}

Measured memory_bytes: 384