awk '
{
    for(i=1;i<=length($0);i++){
        ch = substr($0, i, 1)
        if(ch ~ /[0-9]/){
            d = ""
            while(ch ~ /[0-9]/){
               d = d ch
               ch = substr($0, ++i, 1)
            }
            pat = substr($0, i, d)
            multi[pat]++
            i += (d-1)
       }
        else if(ch ~ /[a-zA-Z]/){
            single[ch]++
        }
    }
}
{
    printf "%s", $0
    for (s in single){
       printf " %d:%s", single[s], s
       delete single[s]
    }

    for (s in multi){
      m == "" ? m=" "multi[s]":"s : m=m"; "multi[s]":"s
      delete multi[s]
    }
    print m
    m = ""
}' beca123456.file