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

int main(void)
{
    char string[10000] = {};
    int l,i,sum = 0;
    scanf("%s",string);
    l = strlen(string);
    for (i = 0;i < l;i++){
        if(isdigit(string[i])){
            sum += (string[i]-'0');
        }
    }
    printf("%d\n",sum);
    return 0;
}