#include<stdio.h>
#include<stdlib.h>

typedef struct node{
    char data;
    struct node*left,*right;
}Node;

Node*root=NULL;

Node  *create(int ch){
    Node*newNode=(Node*)malloc(sizeof(newNode));
    
    newNode->data=ch;
    newNode->left=NULL;
    newNode->right=NULL;
    
    return newNode;
}
Node*insert(Node*root,int ch){
    if(root == NULL) return create(ch);
    if(ch < root->data){
        root->left=insert(root->left,num);
    }
    else if(ch > root->data){
        root->right=insert(root->right,num);
    }
    return root;
}
void inorder(Node*root){
    if(root!=NULL){
        printf("%d ",root->data);
        inorder(root->left);
        inorder(root->right);
    }
}
int main(){
    int size,num,ind;
    scanf("%d",&size);
    
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(ind=0;ind<=size;ind++){
        scanf(" %c ",&ch);
    root =insert(root,ch);
    }
    inorder(root);
    return 0;
    
    
}