#include <iostream>
#include <vector>
using namespace std;

int main() {

    int N = 4;
    int M = 4;

    vector<vector<int>> field = {
        {1,1,0,0},
        {0,1,0,1},
        {0,0,0,1},
        {1,0,0,0}
    };

    vector<vector<bool>> visited(N, vector<bool>(M, false));

    int dx[4] = {-1,1,0,0};
    int dy[4] = {0,0,-1,1};

    int count = 0;

    for(int i=0;i<N;i++){
        for(int j=0;j<M;j++){

            if(field[i][j] == 1 && !visited[i][j]){

                count++;  // 새로운 덩어리 시작

                vector<pair<int,int>> stack;
                stack.push_back({i,j});
                visited[i][j] = true;

                while(!stack.empty()){

                    pair<int,int> cur = stack.back();
                    stack.pop_back();

                    int x = cur.first;
                    int y = cur.second;

                    for(int k=0;k<4;k++){
                        int nx = x + dx[k];
                        int ny = y + dy[k];

                        if(nx>=0 && nx<N && ny>=0 && ny<M){
                            if(field[nx][ny]==1 && !visited[nx][ny]){
                                visited[nx][ny] = true;
                                stack.push_back({nx,ny});
                            }
                        }
                    }
                }
            }
        }
    }

    cout << count << endl;

    return 0;
}