I have a file input.txt, in bash using sed,awk or shell script how can I get the only differed string in a column amount all? 

For example:

```
# cat input.txt
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1axxxxx  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fayyyyyy1c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz
878933fa4965c31c88ee8696a1a5838f  abc xyz

```

I want to pick and display only "878933fa4965c31c88ee8696a1axxxxx" and "878933fayyyyyy1c88ee8696a1a5838f"