#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
//namaega184
int main(){
	char s[10001];int len,ans=0;scanf("%s",s);
	len=strlen(s);
	for(int i=0;i<len;i++)if(s[i]>='0'&&s[i]<='9')ans+=s[i]-'0';
	printf("%d\n",ans); 
	return 0;
}