from itertools import accumulate

from bisect import bisect

def fracKnapsack(vl, wt, W, n):

r = list(sorted(zip(vl,wt), key=lambda x:x[0]/x[1],reverse=True))

vl , wt = [i[0] for i in r],[i[1] for i in r]

acc=list(accumulate(wt))

k = bisect(acc,W)

return 0 if k == 0 else sum(vl[:k])+(W-acc[k-1])*(vl[k])/(wt[k]) if k!=n else sum(vl[:k])

print("%.0f"%fracKnapsack([60, 100, 120],[10, 20, 30],50,3))