#include <iostream>
#include <math.h>

int main(void){

  std::string a;
  int x[9]={0,0,0,0,0,0,0,0,0};
  int y=0;
  
  std::cin >> a;
  const char* ca = a.c_str();
  for(int i=0;i<9;i++){
    x[i]=(int)ca[i]-48;
    //std::cout << x[i] << std::endl;
    if(x[i]==0) x[i]=10;
    y+=x[i];
  }
  std::cout << y << std::endl;
}