tree = {}
    for i in range(0, len(t_from)):
        n1, n2 = t_from[i], t_to[i]
        tree[n1] = tree.get(n1, []) + [n2]
        tree[n2] = tree.get(n2, []) + [n1]
    
    cuts = 0 
    visited = set()
    
    def dfs_helper(node, visited):
        nonlocal cuts
        if node in visited: return 0
        elif tree.get(node, False) is False: return 0
        visited.add(node)
        count = 1
        for child in tree[node]:
            child_count = dfs_helper(child, visited)
            if child_count == 0: continue
            elif child_count % 2 == 0:
                cuts += 1
            else:
                count += child_count
        return count

    dfs_helper(1, visited)
    return cuts