package main

import (
	"fmt"
	"strconv"
	"strings"
)

var in string
var p string
var f string
var sum int

func main() {
	fmt.Scanf("%s", &in)
	for _, d := range strings.Split(in, "") {
		if p == "" {
			f = d
		} else if p == d {
			incr, _ := strconv.Atoi(p)
			sum += incr
		}
		p = d
	}
	if f == p {
		incr, _ := strconv.Atoi(p)
		sum += incr
	}
	fmt.Println(sum)
}