C :

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

C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    cout<<n/100+n/10%10+n%10;
}

Java :

import java.util.Scanner;

public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		
		System.out.println(x/100%10+x/10%10+x%10);
		
	}

}

Python :

a=int(input())
b=a//100
c=a//10%10
d=a%10
print(b+c+d)