#include<stdio.h>
#include<string.h>
int main(void)
{
  char s[10001];
  scanf("%s",s);
  int i;
  int sum=0;
  for(i=0;i<strlen(s);i++){
    switch(s[i]){
    case 0x31:sum+=1;break;
    case 0x32:sum+=2;break;
    case 0x33:sum+=3;break;
    case 0x34:sum+=4;break;
    case 0x35:sum+=5;break;
    case 0x36:sum+=6;break;
    case 0x37:sum+=7;break;
    case 0x38:sum+=8;break;
    case 0x39:sum+=9;break;
    }
  }
  printf("%d\n",sum);
  return 0;
}