class Solution:

    def shortestAlternatingPaths(self, n: int, red_edges, blue_edges):

        def function(n,r,b):

            result=[[float("inf")]* for _ in range(n)]

            result[]=[,]

            r.sort()

            b.sort()

            rdict={}

            bdict={}

            state=

            for i in range(len(r)):

                if r[i][] not in rdict:

                    rdict[r[i][]]=[r[i][]]

                else:

                    rdict[r[i][]].append(r[i][])

            for i in range(len(b)):

                if b[i][] not in bdict:

                    bdict[b[i][]]=[b[i][]]

                else:

                    bdict[b[i][]].append(b[i][])

            while state==:

                state=

                for i in range(n):

                    if i in rdict:

                        for j in rdict[i]:

                            if result[j][]>result[i][]+:

                                state=

                            result[j][]=min(result[j][],result[i][]+)

                    if i in bdict:

                        for j in bdict[i]:

                            if result[j][]>result[i][]+:

                                state=

                            result[j][]=min(result[j][],result[i][]+)

            tmpresult=[]

            for i in range(len(result)):

                if min(result[i])==float("inf"):

                    tmpresult.append(-)

                else:

                    tmpresult.append(min(result[i]))

            return tmpresult

        return function(n,red_edges,blue_edges)