package main

import "fmt"

func main() {
	var s string
	fmt.Scan(&s)
	ans := 0
	for i := 0; i < len(s); i++ {
		if '0' <= s[i] && s[i] <= '9' {
			ans += int(s[i] - '0')
		}
	}
	fmt.Println(ans)
}