##include <stdio.h>
#include <string.h>
#include <ctype.h>
int main (){
    int n;
    scanf("%d",&n);
    char names[n][30];
    int tail=0;
    for (int i=0;i<n;i++)
    {
        scanf("%s",names[tail]);
        for (int j=0;j<strlen(names[tail]);j++)
        {
            if (!isalnum(names[tail][j]))
            {
                printf("Invalid input\n");
                return 0;
            }
        }
        tail++;
    }
    for (int i=0;i<tail;i++)
    {
        printf("%s", names[i]);
        if (i!=tail-1)
        {
            printf(" ");
        }
    }
      return 0;  
}
nt main (){
    int n;
    scanf("%d",&n);
    char names[n][30];
    int tail=0;
    for (int i=0;i<n;i++)
    {
        scanf("%s",names[tail]);
        for (int j=0;j<strlen(names[tail]);j++)
        {
            if (!isalnum(names[tail][j]))
            {
                printf("Invalid input\n");
                return 0;
            }
        }
        tail++;
    }
    for (int i=0;i<tail;i++)
    {
        printf("%s", names[i]);
        if (i!=tail-1)
        {
            printf(" ");
        }
    }
      return 0;  
}