break_cycles_dfs

def dfs(node, destination, graph, visited):
    if node in visited:
        return
    visited.add(node)
    if node == destination:
        return
    for child in graph[node]:
        dfs(child, destination, graph, visited)


def path_exists(source, destination, graph):
    visited = set()
    dfs(source, destination, graph, visited)

    return destination in visited


num = int(input())
graph = {}
edges = []

for _ in range(num):
    parent, children = input().split('->')
    parent, children = parent.strip(), children.strip()
    if children == '':
        graph[parent] = []
    else:
        graph[parent] = children.split(' ')
    for child in graph[parent]:
        edges.append((parent, child))

removed_edges = []

for source, destination in sorted(edges, key=lambda x: (x[0], x[1])):
    if source not in graph[destination] or destination not in graph[source]:
        continue
    graph[source].remove(destination)
    graph[destination].remove(source)

    if path_exists(source, destination, graph):
        removed_edges.append(f'{source} - {destination}')
    else:
        graph[source].append(destination)
        graph[destination].append(source)

print(f'Edges to remove: {len(removed_edges)}')
print('\n'.join(removed_edges))