C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
    int c;
    cin>>c;
	int d = c % 10;
	int b = c / 10 % 10;
	int a = c / 100;
	cout<<a + b + d<<endl; 
   return 0;
}

Pascal :

var a,b,c,d:longint;
begin
read(a);
b:=a mod 10;
c:=a div 10 mod 10;
d:=a div 100;
write(c+b+d);
end.

Java :

import java.util.Scanner;
public class Main{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
  int m = sc.nextInt();
  int s;
  int a = m/100%10;
  int b = m/10%10;
  int c = m/1%10;
  s=a+b+c;
  System.out.print(s);
sc.close();
}
}

Python :

n=int(input())
b=n//100
s=n//10%10
g=n%10
print(b+s+g)