#include<stdio.h>
#include<string.h> 
main()
{
	char s1[20];
	char s2[20];
	scanf("%s",s1);
        int l=0,i=0,c=0;
	while(s1[i]!='\0')
		{
		i++; l++;
		}
		for(i=0;i<l;i++)
		      	{
		         if((int)s1[i]>=65&&(int)s1[i]<=90||(int)s1[i]>=97&&(int)s1[i]<=122)
                           	{
					
			      s2[c]=s1[i];c++;

                 		}	
                       		
		        
                                
			 }
			 i=0;                
				while(s2[i]!='\0')
					{
                        		 printf("%c",s2[i]);
         				 i++;

                			       }
 }