#include <stdio.h>

int main(void)
{
	char s[10001];
	int i,ans;
	scanf("%s",s);

	ans = 0;
	for (i=0;i<10001;i++) {
		if (s[i]=='\0') break;
		if (s[i]>='0' && s[i]<='9') ans += s[i] - '0';
	}

	printf("%d\n",ans);

	return 0;
}