#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int n,s=0; cin>>n; while(n!=0){ int g = n%10; n=n/10; s=s+g; } cout<<s<<endl; return 0; }