#include<stdio.h>
#include<string.h>
#include<ctype.h>
struct Visitor{
    char name[100];
    struct Visitor *tail;
};
int isValidName(char name[]){
    for (int i = 0; name[i] != '\0'; i++){
        if (!isalnum(name[i]))
        return 0;
    }
    return 1;
    
}
int  main(){
    int n;
    scanf("%d", &n);
    
    struct Visitor visitors[1000];
    for (int i = 0; i < n; i++){
        scanf("%s", visitors[i].name);
        if (!isValidName(visitors[i].name)){
            printf("Invalid Input\n");
            return 0;
        }
        if (i < n - 1)
            visitors[i].tail = &visitors[i + 1]]
        else
        visitors[i].tail = NULL;
    }
    struct Visitor *ptr = &visitors[0];
    while (ptr != NULL){
        printf("%s",ptr->name);
        if (ptr->tail !=NULL) printf(" ");
        ptr = ptr->tail;
    }
    return 0;
}