#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("Invaid input");
        return 0;
        
    }
    for (int i=0; str[i] !='\0';i++) {
        if (isalpha(str[i])) {
            c++;
        }
    }
    printf("%d",c);
}