#include <stdio.h>
int main()
{
    int n=0,sum=0,du;
    while (n<=0)
    {
        printf("Vui long nhap n:");
        scanf("%d",&n);
    }
    while (n!=0)
    {
       
        du=n%10;
       sum =sum+du;
        n=n/10;
       
    }
    printf("Tong cac chu so la:%d",sum);
    return 1;
}