package main

import (
    "bufio"
    "fmt"
    "os"
)

func main() {
    scanner := bufio.NewScanner(os.Stdin)
    for scanner.Scan() {
        str := scanner.Text()
        if len(str) == 0 {
            break
        }

        arr := [501]bool{}
        for _, num := range string(str) {
            if num >= 0 && num <= 127 {
                arr[num] = true
            }
        }

        var times int
        for _, item := range arr {
            if item {
                times++
            }
        }
        fmt.Println(times)
    }
}