30. 秘密差

int main() {
    int x;
    scanf("%d", &x);
    int a = 0, b = 0;
    while (x > 0) {
        a += (x % 10);
        x = x / 10;
        b += (x % 10);
        x = x / 10;
    }
    if (a > b) {
        printf("%d", a - b);
    }
    else {
        printf("%d", b - a);
    }
}