#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main() {
    char str[201];
    int letters = 0; isNumber = 1;
    fgets(str, sizeof(str), stdin);
    str [strcspn(str, "\n")] = '\0';
    for (int i = 0; str[i] != ''\n'; i++){
        if(!isdigit(str[i])) {
            isNumber = 0;
            break;
        }
    }
    if (isNumber){
        printf("Invalid Input");
        return 0;
    }
    for (int i = 0; str[i] != '\0'; i++) {
        if (isalpha(str[i])) {
            letters++;
        }
    }
    printf("%d", letters);
    return 0;
}