#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main() {
    char name[100];
    fgets(name, sizeof(name), stdin);
    name[strcspn(name, "\n")] ='\0';
    if (strlen(name) == 0) {
        printf("Invalid input");
        return 0;
    } 
    for (int i = 0; name[i] != '\0'; i++) {
        if (!isalpha(name[i]) && name[i] != ' ') {
            printf("Invalid input");
            return 0;
        }
        int len = strlen(name);
        for (int i = 1; i <= len; i++) {
            for (int j = 0; j < i; j++) {
                printf("%c",name[j]);
            }
            printf("\n");
    }
    return 0;