#include<stdio.h>


int main(void){
    char a[10002];
    int sum = 0;

    fgets(a, sizeof(a), stdin);
    for(int i = 0; a[i] != '\0'; i++) if(a[i] >= '0' && a[i] <= '9') sum += a[i] - '0';

    printf("%d", sum);
    

    return 0;
}