#include<stdio.h>
int madhan(int n)
{
    int temp=0,sum=0;
    while(n!=0)
    {
       temp=n%10;
       sum+=temp;
       n=n/10;
    }
    return sum;
}
int main()
{
    int n;
    scanf("%d",&n);
    madhan(n);
    printf("%d",sum);
}