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

typedef struct node{
    char data;
    struct node *left, *right;
}Node;
Node* root=NULL;
Node* create(char val){
    Node* newNode = (Node*)malloc(1*sizeof(Node));
    newNode->data = val;
    newNode->left = NULL;
    newNode->right = NULL;
    return newNode;
}
Node* insert(Node* root, char val){
    if(root==NULL){
        return create(val);
    }
    if(val < root->data){
        root->left = insert(root->left,val);
    }
    else if(val > root->data){
        root->right = insert(root->right,val);
    }
    return root;
}

void inOrder(Node* root){
    if(root != NULL){
        inOrder(root->left);
        printf("%c ",root->data);
        inOrder(root->left);
    }
}

int main(){
    int size,i,val;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    for(i=1;i<=size;i++){
        scanf("%c ",&val);
        root = insert(root,val);
    }
    inOrder(root);
    return 0;
}