#include<stdio.h>

int main(){

int hash[128] = {0};
char chareacter;
while(chareacter!='\n'){
    chareacter=getchar();
    hash[chareacter] = 1;
}
int ans =0;
for (int i=0; i<128; i++){
    if (hash[i] == 1){
        ans+=1;
    }
}
printf("%d", ans-1);
return 0;

}