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

int main()
{
    char name[20];
    fgets(name, sizeof(name), stdin);
    name[strcspn(name,"\n")] = '\0';
    int len = strlen(name);
    
    if(len == 0)
    {
        printf("Invalid input");
        return 0;
    }
    for(int i = 0; i < len; i++)
    {
        if(isdigit(name[i]))
        {
            printf("Invalid input");
            return 0;
        }
    }
    for(int i = 1; i <= len; i++)
    {
        for(int j = 0;j < i)
    }
}