#include <stdio.h>
#include <stdlib.h>

// 531 ---> 531 / 10 = 53
// units 1
// tens = 3
// hundreds = 5

int main()
{
    int num;
    int units, tens, hundreds;

    printf("Enter a 3-digit number: ");
    scanf("%d", &num);

    units = num % 10;
    tens = (num / 10) % 10;

    hundreds = num / 100;

    printf("The total sum of digits in %d is %d\n", num, units + tens + hundreds);

    return 0;
}