#include <iostream>
 #include <cstring>
 char a[100];
 using namespace std;
 int main()
{long long long f;
 int b,c,sum,n[100],i;
 for (i=0;i<strlen(a);i++)
 {
 cin>>n[i];
 b=n[i]%10;
 n[i]=n[i]/10;
 c=n[i]%10;
 n[i]=n[i]/10;
 }

 for (int i=0;i<strlen(a);i++)
 {
 i=n[i]%10; n[i]=n[i]/10;
 sum=sum+i;
 }
 cout<<sum;
 return 0;
}