#include <stdio.h>
int main() {
  int a,b,c,d,e,f;
scanf("%d",&a);
  b=a/10000;
  c=(a%10000)/1000;
  d=(a%1000)/100;
  e=(a%100)/10;
  f=(a%10);
  printf("%d",b+c+d+e+f);
  return 0;

}