#include <stdio.h>
int main(){
    int a,b,c;
    scanf("%d",&a);
    scanf("%d",&b);
    scanf("%d",&c);
    if (a>b){
        if (b>c){
            printf("%d",c-(a*b));
        }
        else{
            printf("%d",b-(a*c));
        }
    }
    if(b>a){
        if (a<c){
            printf("%d",a-(c*b));
        }
    }
return 0;
}

1) a,b,c sequence is already sorted.
2) Try "1 1 1" input. Answer is -1.