excel multiple data onto one line

So I have data in the following layout

     April    May     June      July     August
a       1
a              4
a                       7
a              
a                                         2
b    1
c              1
c                       3

and need it in the following format:

     April    May     June   July    August
 a    1        4       7              2
 b    1
 c              1       3

I have tried various if statements but cant get them all in the same line.