package main

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

func main() {
	rdr := bufio.NewReaderSize(os.Stdin, 10000)
	l, _, _ := rdr.ReadLine()
	str := string(l)
	rlt := 0
	for _, v := range str {
		if v >= '1' && v <= '9' {
			rlt += int(v) - '0'
		}
	}
	fmt.Println(rlt)
}