#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_set>
#include <vector>
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef vector<pair<int, int>> vpii;
typedef vector<pair<ll, ll>> vpll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vc> vvc;
typedef vector<vs> vvs;
typedef vector<vll> vvll;
typedef map<int, int> mii;
typedef set<int> si;
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define irep(it, stl) for (auto it = stl.begin(); it != stl.end(); it++)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\n'
#define STLL(s) strtoll(s.c_str(), NULL, 10)
#define mp(p, q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define fi first
#define se second
// #include <atcoder/all>
// using namespace atcoder;
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T, class U>
inline bool chmax(T& a, U b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T, class U>
inline bool chmin(T& a, U b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline void dump(T& v) {
    irep(i, v) { cout << (*i) << ((i == --v.end()) ? '\n' : ' '); }
}
template <class T, class U>
inline void dump(map<T, U>& v) {
    irep(i, v) { cout << i->first << " " << i->second << '\n'; }
}
template <class T, class U>
inline void dump(pair<T, U>& p) {
    cout << p.first << " " << p.second << '\n';
}
string getline() {
    string s;
    fflush(stdin);
    getline(cin, s);
    return s;
}
inline void yn(const bool b) { b ? fin("yes") : fin("no"); }
inline void Yn(const bool b) { b ? fin("Yes") : fin("No"); }
inline void YN(const bool b) { b ? fin("YES") : fin("NO"); }
template <typename Head, typename Value>
auto vectors(const Head& head, const Value& v) {
    return vector<Value>(head, v);
}
template <typename Head, typename... Tail>
auto vectors(Head x, Tail... tail) {
    auto inner = vectors(tail...);
    return vector<decltype(inner)>(x, inner);
}
const int INF = INT_MAX;
constexpr ll LLINF = 1LL << 61;
constexpr ll MOD = 1000000007;  // 998244353;
constexpr ld EPS = 1e-11;

/* --------------------   ここまでテンプレ   -------------------- */

int main() {
    string s,t;
    cin>>s>>t;
    fin(max((s[0]-'0')+(s[1]-'0')+(s[2]-'0'),(t[0]-'0')+(t[1]-'0')+(t[2]-'0')));
}

#include<iostream>
#include<iomanip>
#include<string>
#include<vector>
#include<algorithm>
#include<utility>
#include<tuple>
#include<map>
#include<queue>
#include<deque>
#include<set>
#include<stack>
#include<numeric>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>

using namespace std;

struct Edge {
  int to;
  long long weight;
  Edge() : to(0), weight(0) {}
  Edge(int to, long long weight) : to(to), weight(weight) {}
  Edge(const Edge& e) {
    to = e.to;
    weight = e.weight;
  }
  bool operator>(const Edge &e) const { return weight > e.weight; }
  bool operator<(const Edge &e) const { return weight < e.weight; }
  bool operator==(const Edge &e) const { return weight == e.weight; }
  bool operator<=(const Edge &e) const { return weight <= e.weight; }
  bool operator>=(const Edge &e) const { return weight >= e.weight; }
};

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using Graph = vector<vector<int>>;
using weightedGraph = vector<vector<Edge>>;
using heap = priority_queue<int, vector<int>, greater<int>>;

const ll BIL = 1e9;
const ll MOD = 1e9 + 7;
const ll INF = 1LL << 60;
const int inf = 1 << 29;
const ld PI = 3.141592653589793238462643383;

struct SegmentTree {
  int sz;
  vector<int> t;
  SegmentTree(int n) {
    sz = 1;
    while(sz < n) sz *= 2;
    t.assign(2 * sz - 1, 0);
  }
  void init(int idx, ll val) {
    idx += sz-1;
    t[idx] = val;
    return;
  }
  // update the maximum value of the interval
  void update(int idx, int val) {
    idx += sz - 1;
    t[idx] = val;
    while(idx > 0) {
      idx = (idx - 1) / 2;
      if(t[idx] > val) break;
      t[idx] = val;
    }
    return;
  }
  // update the sum of the interval
  void update(int l, int r, ll val, int now=0, int a=0, int b=-1) {
    if(now >= t.size()) return;
    if(b < 0) b = sz;
    if(l < 0) l = 0;
    if(r > sz) r = sz;
    if(r < a || l > b) return;
    if(a <= l && r <= b) {
      t[now] += val;
      update(l, r, val, now*2+1, a, (a+b)/2);
      update(l, r, val, now*2+2, (a+b)/2, b);
    }
    return;
  }
  // get the sum of interval
  int getSum(int l, int r, int now=0, int a=0, int b=-1) {
    if(now >= t.size()) return 0;
    if(b < 0) b = sz;
    if(l < 0) l = 0;
    if(r > sz) r = sz;
    if(l > b || r < a) return 0;
    if(l <= a && r >= b) return t[now];
    int res = 0;
    res += getSum(l, r, 2*now+1, a, (a+b)/2);
    res += getSum(l, r, 2*now+2, (a+b)/2, b);
    return res;
  }
  // get the maximum value of the interval
  int getMax(int l, int r, int now=0, int a=0, int b=-1) {
    if(now >= t.size()) return 0;
    if(b < 0) b = sz;
    if(l < 0) l = 0;
    if(r > sz) r = sz;
    if(l > b || r < a) return 0;
    if(l <= a && r >= b) return t[now];
    int res = 0;
    res = max(res, getMax(l, r, 2*now+1, a, (a+b)/2));
    res = max(res, getMax(l, r, 2*now+2, (a+b)/2, b));
    return res;
  }
  ll getElement(int idx) {
    if(idx == 0) return t[0];
    ll res = t[idx];
    return res += getElement((idx-1)/2);
  }
  ll operator[](int idx) {
    idx += sz-1;
    return getElement(idx);
  }
};

int main(int argc,char* argv[]){
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout << fixed << setprecision(20);
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  for(int i=0;i<h;i++) {
    cin >> s[i];
  }
  int ans = 0;
  for(int i=0;i<h-1;i++) {
    for(int j=0;j<w-1;j++) {
      int t = 0;
      for(int k=0;k<2;k++) {
        for(int l=0;l<2;l++) {
          if(s[i+k][j+l] == '#') t++;
        }
      }
      if(t == 1 || t == 3) ans++;
    }
  }
  cout << ans << endl;
  return 0;
}
