class Solution {
public:
   


  
  
  void dfs(vector<vector<char>> &grid,int i,int j,int n,int m)  
  {
      if(i<0 || j<0|| i>=n||j>=m || grid[i][j]=='0'|| grid[i][j]=='v')
      {
          return ;
      }
   
      grid[i][j]='v';
      dfs( grid, i+1, j, n, m);
      dfs( grid, i-1, j, n, m);
      dfs( grid, i, j+1, n, m);
      dfs( grid, i, j-1, n, m);
  
  
  
  
  }
    
    
        int numIslands(vector<vector<char>>& grid)
    {
     int n=grid.size();
     int m=grid[0].size();
        int ans=0;
        for(int i=0;i<n;i++)
        {  for(int j=0;j<m;j++)
           {
               if( grid[i][j]=='1')
               {
                   ans++;
                   dfs( grid, i, j, n, m);
               }
        
          }
        }
        return ans;
    }
    

    
    

};