src = [0,'A',1,'A',3,'A',5,'B',8,'A',13,'A',20,'A']
dst = []
sep = src[src.index('B')-1]
for i in range(0, len(src), 2):
if src[i]>=sep:
dst.append(src[i])
dst.append(src[i+1])
print dst
c3JjID0gWzAsJ0EnLDEsJ0EnLDMsJ0EnLDUsJ0InLDgsJ0EnLDEzLCdBJywyMCwnQSddCmRzdCA9IFtdCnNlcCA9IHNyY1tzcmMuaW5kZXgoJ0InKS0xXQpmb3IgaSBpbiByYW5nZSgwLCBsZW4oc3JjKSwgMik6CiAgICBpZiBzcmNbaV0+PXNlcDoKICAgICAgICBkc3QuYXBwZW5kKHNyY1tpXSkKICAgICAgICBkc3QuYXBwZW5kKHNyY1tpKzFdKQpwcmludCBkc3QK