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

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

Node *root = NULL;

Node *create(char num){
    Node *newnode = (Node*) malloc (1 * sizeof(Node));
    newnode->data = num;
    newnode->left = NULL;
    newnode->right = NULL;
    return newnode;
}

Node *insert(Node *root,char num){
    if(root == NULL){
        return create(num);
    }
    if(num <root->data){
        root->left = insert(root->left,num);
    }
    else if(num > root->data){
        root->right = insert(root->right,num);
    }
    return root;
}

Node *inorder(Node *root){
    if(root!=NULL){
        inorder(root->left);
        printf("%s ",root->data);
        inorder(root->right);
    }
}

int main(){
    int size,ind;
    char num;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(ind=0;ind<size;ind++){
        
        scanf("%s",num);
        root = insert(root,num);
    }
    inorder(root);
    return 0;
}