#include <stdio.h>
int main() {
int a;
scanf("%d",&a);
printf("%d",a/1000 + (a/100)%10 + (a/10)%10 + a%10);
return 0;
} #include <stdio.h>
int main() {
int n = 0, sum = 0;
scanf("%d", &n);
while (n)
{
sum += n % 10;
n /= 10;
}
printf("%d", sum);
return 0;
}