#include <iostream>
using namespace std;

int main() {
	
	int n = 0;		//定义变量
	int sum = 0;
	cin >> n;
	//循环把每一位拿出来
	while (n > 0) {
		int ge = n % 10;
		sum += ge;
		n = n / 10;
	}

	cout << sum;

	system("pause");
	return 0;
 }