class _{public static void main(String[]x)throws Exception{byte[]b=new byte[255];int i;for(;(i=System.in.read())>0;b[i]++);for(i=64;i++<122;)if(b[i]>0)System.out.printf("%c:%3d\n",i,b[i]);}}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).