#include <stdio.h>
int main(void) {
    int a, b, c, max, min, med;
    scanf("%d %d %d", &a, &b, &c);
    max = a >= b && a >= c? a: b >= a && b >= c? b: c;
    min = a <= b && a <= c? a: b <= a && b <= c? b: c;
    med = a + b + c - min - max;
    if (med == 0)
        printf("%d", - max);
    else
        printf("%d", min - max * med);
    return 0;
}

I'd assume something like
0
1
2

1
1
1

answer: -1