#include<stdio.h>

int main(void){
  int i, sum = 0;
  char S[10001];
  scanf("%s", S);
  for(i = 0; S[i] != '\0'; i++){
    if('0' <= S[i] && S[i] <= '9'){
      sum += S[i] - '0';
    }
  }
  printf("%d\n", sum);
  return 0;
}