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

void main(void){
	char str[100000];
    int inputStr =scanf("%s\n",str);
    if(inputStr == 2){
    	printf("文字列の入力ミス\n");
    }
	int sum = 0 , i = 0 ;
	while(str[i] != '\0'){
		int charNum = str[i] - '0';
		if(charNum >= 0 && charNum <= 9){
			sum += charNum;
		}	
	}
	printf("%d\n",sum);
}