#include<stdio.h>
#include<ctype.h>

int main()
{
	char S[10000];
	int i=0;
	int sum=0;
	
	scanf("%s",&S);
	
	while(S[i]!='\0'){
		if(isdigit(S[i]))
			sum+=S[i]-'0';
		i++;
	}
	
	printf("%d\n",sum);
	return 0;
}