#include <stdio.h>

int main() {
    char ch=0;
    char ch1[128]={0};
    int count=0;
    while(scanf("%c",&ch)){
        if(ch=='\n'){
            break;
        }
        if(ch>=0&&ch<=127){
            if(ch1[(int)ch]!=ch){
                ch1[(int)ch]=ch;
                count++;
            }
        }
    }
    printf("%d",count);
    return 0;
}