#include<stdio.h>
#include<string.h>
int main(){
	char p[10001];
	long sum=0;
	int i=0;
	scanf("%s",p);
	while(p[i]!='\0'){
		if(p[i]<='9' && p[i]>='1') sum+=(long)(p[i]-'0');
		i++;
	}
	printf("%ld\n",sum);
	return 0;
}