Can't make it print 0 if false

[ka06059]

a = [int(i) for i in input().split()]
for i in range(1, len(a)):
  if a[i - 1] * a[i] > 0:
    print(a[i - 1], a[i])
    break
  if i >= len(a)-1:  #added line
      print 0        #added line

try add the last 2 lines. 0 printed when eveything is false and the loop meets its end