> #include "stdio.h"
> #include "malloc.h"
> 
> 
> int exchange(int a)
> {
> 	int result=0;
> 
> 	while(a>10)
> 	{
> 		result=result+a%10;
> 		a=a/10;
> 	}
> 	result+=a;
> 
> 	if(result>10)
> 	result=exchange(result);
> 
> 	return result;
> 
> }
> 
> 
> 
> int main()
> {
>   int a[100000]={0},i=0,k=0;
> 
>     while(1)
> 	{
> 		scanf("%d",&a[i]);
> 
> 		
> 		if(a[i]==0)break;
> 	    a[i]=exchange(a[i]);
> 		i++;
> 	}  
> 	while(a[k]!=0)
> 	{
> 		printf("%d\n",a[k]);
> 		k++;
> 	}
>  
> 
> 	return 0;
> }