def sost1(Lista1,Lista2,n,p):
ListaNew=Lista1
for i in range(len(ListaNew)):
if n == ListaNew[i]:
ListaNew[i] = Lista2[p]
return ListaNew
L1 = input()
L2 = input()
N = input()
P = input()
if len(L2) >= P+1:
print sost1(L1,L2,N,P)
else:
print "lista troppo corta"
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WzIsMywgNCwgNSwgMV0KWzMsIDQsIDUsIDEsMl0KMwoz
[2,3, 4, 5, 1]
[3, 4, 5, 1,2]
3
3