C++ :

#include <algorithm>
#include <cstdio>

using namespace std;

const int M = 1e5 + 5;

int n, p, q;
int a, b;
int ans;

int gcd(int a, int b) {
    if (!a || !b) return a + b;
    return gcd(b, a % b);
}

int main() {
    scanf("%d%d%d", &n, &p, &q);
    while (n--) {
        scanf("%d%d", &a, &b);
        if (a == b)
            ans = 0;
        else if (a == 1 || b == 1)
            ans = p;
        else {
            ans = min(p + p, q + q);
            if (gcd(a, b) == 1)
                ans = min(ans, p);
            else
                ans = min(ans, q);
        }
        printf("%d\n", ans);
    }
    return 0;
}