#include <iostream>
using namespace std;

int main() {
    int dadWeight;
    // 读取输入的爸爸体重
    cin >> dadWeight;
    // 计算百位数字
    int hundreds = dadWeight / 100;
    // 计算十位数字
    int tens = (dadWeight / 10) % 10;
    // 计算个位数字
    int units = dadWeight % 10;
    // 计算小明的体重
    int xiaomingWeight = hundreds + tens + units;
    // 输出小明的体重
    cout << xiaomingWeight << endl;
    return 0;
}
    
/**************************************************************
	Problem: 1716
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:20 ms
	Memory:2072 kb
****************************************************************/