// editor3
#include<stdio.h>
#include<ctype.h>
#include<string.h>
int main(){
    char str[200];
    int count=0;
    int digitcount=0;
    int length;
    fgets(str,sizeof(str),stdin);
    str[strcspn(str,"\n")]='\0';
    for(int i=0;str[i]!='\0';i++){
        if(isdigit(str[i])){
            digitcount++;
        }else if(isalpha(str[i])||str[i]==''){
            continue;
        }else{
            continue
        }
    }if(diditcount==strlen(str)){
        printf("Invaild input");
        return 0;
    }
    if(int i=0;str[i]!='\0';i++){
        if(isalpha(str[i])){
            count++;
        }
    }
    printf("%d",count);
    return 0;
}