#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long
#define REP(a,b) for(int a=0;a<(b);++a)
#define REP1(i,n) for(int i=1;i<=(n);++i)
#define debug(x) cerr<<#x<<": "<<x<<'\n'
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define YES() printf("YES\n")
#define NO() printf("NO\n")
#define isYES(x) printf("%s\n",(x) ? "YES" : "NO")
#define Yes() printf("Yes\n")
#define No() printf("No\n")
#define isYes(x) printf("%s\n",(x) ? "Yes" : "No")
#define isPossible(x) printf("%s\n",(x) ? "Possible" : "Impossible")
#define SZ(x) ((int)(x).size())
#define pb push_back
#define mp make_pair
// #define INF (1<<9+9)
const int INF = 0x3fffffff;
// const long long INF = 1LL<<50;

#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
#define pie 3.14159265358979323846

using namespace std;

typedef pair<int, int> P;
typedef pair<ll, ll> LP;
typedef pair<int, P> PP;
typedef pair<ll, LP> LPP;
template<class T=int>
T in(){T x;cin>>x;return (x);}
template<class T>
void print(T& x){cout<<x<<'\n';}

const int MOD =(int)998244353; 
// const int mod =(int)998244353;
const int mod =(int)1e9+7;

const int MAX =510000;
ll fac[MAX],finv[MAX],inv[MAX];
void COMint(){
    fac[0]=fac[1]=1;
    finv[0]=finv[1]=1;
    inv[1]=1;
    for(int i=2;i<MAX;i++){
        fac[i]=fac[i-1]*i%MOD;
        inv[i]=MOD-inv[MOD%i]*(MOD/i)%MOD;
        finv[i]=finv[i-1]*inv[i]%MOD;
    }
}
ll COM(int n,int k){
    if(n<k) return 0;
    if(n<0||k<0)return 0;
    return fac[n]*(finv[k]*finv[n-k]%MOD)%MOD;
}
ll gcd(ll a,ll b){
    if(a<0)a=-a;
    if(b<0)b=-b;
    if(b==0)return a;
    if(a>b){
        swap(a,b);
    }
    return gcd(a,b%a);
}
ll lcm(ll a,ll b){
  if(a<0)a=-a;
  if(b<0)b=-b;
    ll g;g=gcd(a,b);
    return b/g*a;
}
bool compare_by_b(pair<int, int> a, pair<int, int> b) {
    if(a.second != b.second){
        return a.second < b.second;
    }else{
        return a.first < b.first;
    }
}
bool compare_by_a(pair<int, int> a, pair<int, int> b) {
    if(a.first != b.first){
        return a.first < b.first;
    }else{
        return a.second < b.second;
    }
}
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
//int N, M, K, T, H, W, L, R;
// long long int N, M, K, T, H, W, L, R
ll RS(ll N,ll P){
    if(P==0){
        return 1;
    }else{
        if(P%2==0){
            ll t=RS(N,P/2);
            return t*t;
        }else{
            return N*RS(N,P-1);
        }
    }
}
int main() {
    ios::sync_with_stdio(false);
    int N;cin>>N;
    vector<int>v(N);
    REP(i,N)cin>>v[i];
    int ans=INF;
    REP(i,(1<<N-1)){
        int ans_temp=0;
        int or_temp=v[0];
        REP(j,N-1){
            if((i>>j)&1){
                ans_temp=ans_temp^or_temp;
                or_temp=v[j+1];
            }else{
                or_temp|=v[j+1];
            }
        }
        ans_temp=ans_temp^or_temp;
        chmin(ans,ans_temp);
    }
    cout<<ans<<endl;
    return 0;

} 
  

//FIRST THINK THEN CODE.

#include <bits/stdc++.h>


using namespace std;

typedef long long ll;

#define rep(i,a,b) for(ll i=a;i<b;++i)
#define rrep(i,a,b) for(ll i=a;i>b;--i)
#define FOR(i,n)  for(ll i=0;i<n;i++)
#define vi vector<int>
#define vl vector<ll>
#define ld long double
#define vld vector<ld>
#define vvi vector<vector<int>>
#define vvl vector<vector<long long>>
#define vvld vector<vector<ld>>
#define pii pair<int,int>
#define pll pair<long,long>
#define vpii vector<pii>
#define vpll vector<pll>
#define ff first
#define ss second
#define pb push_back
#define pf push_front
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define bs binary_search
#define d1(x) cout<<(x)<<endl
#define d2(x,y) cout<<(x)<<" "<<(y)<<endl
#define d3(x,y,z) cout<<(x)<<" "<<(y)<<" "<<(z)<<endl
#define d4(a,b,c,d) cout<<(a)<<" "<<(b)<<" "<<(c)<<" "<<(d)<<endl
#define PI 3.1415926535897932384626433832795
#define fix(f,n) fixed<<setprecision(n)<<f
#define all(x) x.begin(),x.end()
#define rev(p) reverse(p.begin(),p.end());
#define endl "\n"
#define IOS ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define popcount(x) __builtin_popcountll(x)
#define sz(x) ((ll)x.size())
const ll M = 1000000007;
const ll MM = 998244353;
ll begtime = clock();
#define end_routine() cout << "\n\nTime elapsed: " << (clock() - begtime)*1000/CLOCKS_PER_SEC << " ms\n\n";
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//#define trace(...)
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cout << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ','); cout.write(names, comma - names) << " : " << arg1 << " | "; __f(comma + 1, args...);
}

template<typename T, typename F>
void chmax( T &a, F b) {
  if (b > a)a = b;
}

template<typename T, typename F>
void chmin( T &a, F b) {
  if (b < a)a = b;
}



/* if you want to multiply 2 64 bit numbers mod c.
 i.e a*b%c.
 this function will help  in preventing "overflow".
*/

ll mulmod(ll a, ll b, ll c) {

  ll ans = 0;
  ll y = a % c;
  while (b) {
    if (b & 1) {
      (ans += y) %= c;
    }
    y = y * 2 % c;
    b >>= 1;
  }
  return ans;

}



ll powM(ll a, ll b, ll m)
{
  if (a <= 0)return 0;
  a %= m;

  ll ans = 1LL;
  while (b)
  {
    if (b & 1)ans = ans * a % m;
    //ans = mulmod(ans, a, m);
    a = a * a % m;
    //a = mulmod(a, a, m);
    b >>= 1;
  }

  return ans;
}

ll powMbig(ll a, ll b, ll m)
{
  if (a <= 0)return 0;
  a %= m;

  ll ans = 1LL;
  while (b)
  {
    if (b & 1)//ans = ans * a % m;
      ans = mulmod(ans, a, m);
    //a = a * a % m;
    a = mulmod(a, a, m);
    b >>= 1;
  }

  return ans;
}




ll poww(ll a, ll b)
{

  ll ans = 1;
  while (b)
  {
    if (b & 1)ans = ans * a;
    a = a * a;
    b >>= 1;
  }

  return ans;

}


string tostring(ll x) {
  stringstream sss;
  sss << x;
  string ans = sss.str();
  return ans;
}



const ll N = 2e5 + 5;



int main() {

  IOS;

#ifndef ONLINE_JUDGE

  freopen("input1.txt", "r", stdin);
  freopen("output1.txt", "w", stdout);

#endif


  ll h, w;

  cin >> h >> w;

  string g[h];

  FOR(i, h)cin >> g[i];

  ll ans = 0;

  vl a;
  ll c;
  for (ll i = 0; i < h; i++) {
    c = 0;
    for (ll j = 0; j < w; j++) {
      if (g[i][j] == '.')c++;
      else {
        // d1(c);
        ans += max(0ll, c - 1);
        c = 0;
      }
    }
    ans += max(0ll, c - 1);
  }


  for (ll j = 0; j < w; j++) {
    c = 0;
    for (ll i = 0; i < h; i++) {
      if (g[i][j] == '.')c++;
      else {
        //cout << "h" << " " << c << endl;
        ans += max(0ll, c - 1);
        c = 0;
      }
    }
    ans += max(0ll, c - 1);
  }

  cout << ans << endl;

  return 0;
}