#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main()
{
    char tittle[1000];
    if(fgets(tittle,sizeof(tittle),stdin)==NULL)
    {
        return 1;
    }
    tittle[strcspn(tittle,"\\n")]=0;
    int is_integer=1;
    for(int i=0;tittle[i]!= NULL;i++)
    {
        if(!isdigit(tittle[i]))
        {
            is_integer=0;
            break;
        }
    }
    int i;
    if(is_integer && tittle[i]!=NULL)
    {
        printf("Invalid input\\n");
    }
    else
    {
        int count=0;
        for(i=0;tittle[i]!=NULL;i++)
        {
            if(isalpha(tittle[i]))
            {
                count++;
            }
        }
        printf("%d\\n",count);
    }
    return 0;
}