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

struct Node {
    int data;
    struct Node* prev;
    struct Node* next;
}

struct Node* createNode(int data) {
    Struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->prev = NULL;
    newNode->next = NULL;
    return newNode;
}
void append(struct Node** head, int data) {
    struct Node* newNode = createNode(data);
    if(*head == NULL) {
        *head = newNode;
        return;
    }
    struct Node* temp = *head;
    while(temp->next != NULL) {
        temp = temp->next;
    }
    temp->next= newNode;
    newNode->prev = temp;
}
void sortlist(struct Node* head) {
    struct Node* i;
    struct Node* j;
    int temp
    for (i =head; i !=NULL; i = i->next) {
        for (j = i->next; j !=NULL; j = j->next) {
            if (i->data > j->data) {
                temp = i->data;
                i->data = j->data;
                j->data = temp
            }
        }
    }
}
void printlist(struct Node* head) {
    struct Node* temp = head;
    while (temp != NULL) {
        printf("%d", temp->data);
        temp= temp->next;
        temp= temp->next;
    }
    printf("\n");
}
int main() {
    int n;
    if (scanf("%d",&n) !=1 || n<1 || n>1000) {
        printf("Invalid input\n");
        return 0;
    }
    
    struct Node* head = NULL;
    for (int i=0;i<n;i++) {
        char buffer[50];
        if (scanf("%s", buffer) !=1) {
            printf("Invalid input\n");
            return 0;
        }
        for (int k = 0; k < strlen(buffer); k++) {
            if (!isdigit(buffer[k] && !(k==0 && buffer[k]=='-')) {
                printf("Invalid input\n");
                return 0;
            }
        }
        int value = atoi(buffer);
        append(&head, value);
}
sortlist(head);
printlist(head);
return 0;
}