static int calculate(int a, int b, int(*function)(int, int)){
    return (*function)(a, b);
}

static int plus(int a, int b){
    return a + b;
}

static int minus(int a, int b){
    return a - b;
}

int main(){
    int sum = calculate(5, 10, &plus);
    int diff = calculate(10, 5, &minus);

    return sum - diff;
}