# Sample graph represented as an adjacency list
#dictionary

graph = {
'A': ['B', 'C'],
'B': ['D', 'E'],
'C': ['F'],
'D': [],
'E': ['F'],
'F': []
}

visited = set()

def dfs(graph, vertex):

  visited.add(vertex)
  print(vertex)

  for neighbor in graph[vertex]:
    if neighbor not in visited:
      dfs(graph, neighbor)

# Starting DFS from vertex 'A'
dfs(graph, 'A')