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

int main() {
    
    char str[1000];
    int c = 0;
    int isDigitOnly = 1;
    
    fgets(str, sizeof(str), stdin);
    
    for(int i=0; str[i] != '\0' && str[i] != '\n'; i++){
        if(!isdigit(str[i])) {
            isDigitOnly = 0;
            break;
        }
    }
    if(isDigitOnly) {
        printf("Invalid input");
        return 0;
    }
    for (int i=0; str[i] != "\0"; i++) {
        if (isalpha(str[i])) {
            c++;
        }
    }
    printf("%d",c);
}