#include <iostream>

int main() {
    int dadWeight;
    std::cin >> dadWeight;

    int hundreds = dadWeight / 100;
    int tens = (dadWeight / 10) % 10;
    int units = dadWeight % 10;

    int xiaomingWeight = hundreds + tens + units;

    std::cout << xiaomingWeight << std::endl;

    return 0;
}    
/**************************************************************
	Problem: 1716
	User: fuyijun
	Language: C++
	Result: Accepted
	Time:19 ms
	Memory:2072 kb
****************************************************************/