def treeLength(tree, node, count):
    if tree.get(node):
        for n in tree[node]:
            count = treeLength(tree, n, count + 1)
    return count

def evenForest(t_nodes, t_edges, t_from, t_to):
    graph = {}
    for i in range(t_edges):
        if t_to[i] in graph:
            graph[t_to[i]].append(t_from[i])
        else:
            graph[t_to[i]] = [t_from[i]]
    count = 0
    for e in graph:
        for n in graph[e]:
            length = treeLength(graph, n, 1)
            if not length % 2:
                count += 1
    return count