class Solution:

def canFinish$($self$,$ numCourses: int, prerequisites: List$[$List$[$int$]])->$ bool:

n $=$ numCourses

graph $=[[]$ for i in range$($n$)]$

g $=[0]*$n

for v$,$ u in prerequisites:

graph$[$u$].$append$($v$)$

g$[$v$]+=1$

S $=[$v for v in range$($n$)$ if g$[$v$]==0]$

while S:

u $=$ S$.$pop$()$

for v in graph$[$u$]$:

g$[$v$]-=1$

if g$[$v$]==0$:

S$.$append$($v$)$

return not any$($g$)$