#!/usr/bin/awk -f

#
# Sort the indices as strings in ascending order
#
BEGIN{
    PROCINFO["sorted_in"]="@ind_str_asc"
}

#
# Make a frequency table of the first letter of each word
#
{
    freq[substr($1,1,1)]++
}

#
# Print the results in the frequency table
#
END{
    for (i in freq)
        printf "%s: %d\n",i,freq[i]
}