#include <stdio.h>

int main(void){
	char string[10001] = {};
	int i,result;

	scanf("%s",string);

	i = 0;
	result = 0;
	while(string[i] != '\0' && i <=10000){
		if(string[i] >= '0' && string[i]<= '9'){
			result += string[i]-'0';
		}
		i++;
	}
	printf("%d\n",result);

	return 0;
}