def METHOD_NAME():
    parents = {}
    queue = deque([s])
    while queue:
        if t in parents:
            break
        u = queue.popleft()
        for v in R_succ[u]:
            attr = R_succ[u][v]
            if v not in parents and attr["capacity"] - attr["flow"] > 0:
                parents[v] = u
                queue.append(v)
    return parents