I need to set a label for each id in column a, based on the existing values for this id. For example, if the id 1 only has "F" then the result will be "Female", if only "M" then "Male" and if mixed, then "Mixed".

This is the dataframe base:

```
    df=data.frame(
      a=c(1,1,1,2,2,3,3,3,3,3),
      b=c("F","M","F","M","M","F","F","F","F","F"))

```

And this is the expected result:

```
    df$Result=c("Mixed", "Mixed", "Mixed", "Male", "Male", "Female", "Female", "Female", "Female", "Female")

       a b Result
    1  1 F  Mixed
    2  1 M  Mixed
    3  1 F  Mixed
    4  2 M   Male
    5  2 M   Male
    6  3 F Female
    7  3 F Female
    8  3 F Female
    9  3 F Female
    10 3 F Female

```

Someone could please help me to calculate this `df$Result` column? Thanks in advance!