这张图有几块，各多大

七个点的图。运行下面这段程序：

def blocks(g):
    seen = set()
    out = []
    for s in sorted(g):
        if s in seen:
            continue
        blk = []
        st = [s]
        seen.add(s)
        while st:
            u = st.pop()
            blk.append(u)
            for v in g[u]:
                if v not in seen:
                    seen.add(v)
                    st.append(v)
        out.append(sorted(blk))
    return out

g = {0: [1, 2], 1: [0, 3], 2: [0, 4],
     3: [1, 4], 4: [2, 3], 5: [6], 6: [5]}
b = blocks(g)
print(str(len(b)) + "/" + "/".join(str(len(x)) for x in b))