Extract letters from a column

Dear list:

I would like to extract three letters from first and second elements
in one column and make a new column.

For example below,

tempdf = read.table("clipboard", header=T, sep='\t')
tempdf

name var1 var2    abb
1      Tom Cruiser    1    6 TomCru
2       Bread Pett    2    5 BrePet
3 Arnold Schwiezer    3    7 ArnSch

(p1 = substr(tempdf$name, 1, 3))

[1] "Tom" "Bre" "Arn"

I was able to extract three letters from first name, however, I don't
know how to extract three letters from last name (i.e., 'Cru', 'Pet',
and 'Sch').  Can anyone give me a suggestion?  Many thanks in advance.

Best,

Steve