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