#include <stdio.h>

int main() {
    int n = 0;
    scanf("%d", &n);
    int sum = 0;
    if(n<0){
        n = -n;
        while(n){
        sum = sum + n%10;
        n = n/10;
        }
    }
    else{
        while(n){
        sum = sum + n%10;
        n = n/10;
        }
    }
    printf("%d", sum);
    return 0;
}