/*
                                                                   .odNMMmy:
                                                                   /MMMMMMMMMy
                                                                  `NMMMMMMMMMM:
                                                                   mMMMMMMMMMM-
                                `::-                               -dMMMMMMMN/
                    `+sys/`    sNMMMm/   /ydho`                      :oyhhs/`
                   :NMMMMMm-  -MMMMMMm  :MMMMMy  .+o/`
                   hMMMMMMMs   sNMMMm:  `dMMMN/ .NMMMm
                   -mMMMMMd.    `-:-`     .:-`  `hMMNs -syo`          .odNNmy/        `.
                    `:oso:`                       `.`  mMMM+         -NMMMMMMMy    :yNNNNh/
                       `--.      :ydmh/    `:/:`       -os+`/s+`     sMMMMMMMMM`  +MMMMMMMMs
                     .hNNNNd/   /MMMMMM+  :mMMMm-   ``     -MMM+     -NMMMMMMMy   hMMMMMMMMN
            ``       mMMMMMMM-  :MMMMMM/  oMMMMM/ .hNNd:    -/:`      .odmmdy/`   :NMMMMMMN+
         -sdmmmh/    dMMMMMMN.   -shhs:   `/yhy/  /MMMMs `--`           ````       .ohddhs-
        :NMMMMMMMy   `odmNmy-                      /ss+``dNNm.         .-.`           ``
        yMMMMMMMMM`    ``.`                             `hNNh.       /dNNNms`      `-:-`
        :NMMMMMMMs          .--.      /yddy:    .::-`    `..`       /MMMMMMMh    `smNNNms`
         .ohdmdy:         -hmNNmh:   +MMMMMM/  /mMMNd.   ``         :MMMMMMMy    oMMMMMMMs   `-::.
            ```  ``      `NMMMMMMN.  +MMMMMN:  yMMMMM- -hmmh-        /hmNNdo`    +MMMMMMM+  +mNMNNh-
              -sdmmdy:   `mMMMMMMN`   :yhhs-   `+hhy:  oMMMMo          ...`       /hmmmh/  :MMMMMMMm
             /NMMMMMMNo   .sdmmmy-                     `+yy/`     -+ss+.            `.`    .NMMMMMMh
             dMMMMMMMMN     `..`                                 /NMMMMm-      :shyo.       -sdmmh+`
     `       /NMMMMMMMo                 .-.                      oMMMMMM/     sMMMMMm.        ```
 `/ydddho-    -sdmmdy:                `hNNms                     `odmmd+      yMMMMMN-   -shhs:
-mMMMMMMMNo     ````           `--.   `mMMMm                 `-//- `..        `odddy:   :NMMMMN/
mMMMMMMMMMM:            .//.   yNMN/   .+o/.                `dMMMNo       ./o+-  ``     /MMMMMM+
mMMMMMMMMMM:            dMMd   ommd:     -+o/.              .NMMMMy      -mMMMN+         /hddh/
:mMMMMMMMNs             -oo-    .:.     +NMMMm-         .//- -shy+`      -NMMMMo    `/oo:`  `
 `+ydmmdo-            `ohy/    smmdo    oMMMMN:        /NMMN+       `:++- -oso:    `dMMMMh
     ``               /MMMm   `NMMMN`    :oso-         :mMMN/       oMMMM/         `mMMMMh
                       :o+-    -oyo-         -+oo:`     .::.   -oo: /mNNm-     -+o/``/ss/`
                      `:oo:      .:/-`      oMMMMMh`          `NMMM- `--`     :MMMMy
                      oMMMM/    :mMMMm-     mMMMMMM.           +hho`     .+s+`.dNNm+
                      :mNNd-    oMMMMM/     -hmNNd/                 -o+. hMMMo  .-`
                       `..``    `/yhy/        `.`  `:oss+.          mMMh -shs.
                        :ydds.       .://.        `hMMMMMN+         -+/.
                       .MMMMMm      +NMMMMy       /MMMMMMMm
                        yNNNN+      mMMMMMM-      `dMMMMMN+    ````
                         .--` ``    :dNNNmo         :oss+.   -ydNNmh/
                            /hmmh+`   .--`  ./++:`          /MMMMMMMMy
                           :MMMMMMs        yMMMMMm/         hMMMMMMMMM      `-::-`
                           -NMMMMM+       /MMMMMMMN         :NMMMMMMMo    -yNMMMMMh:
                            .oyys-   ``   `mMMMMMMs          .ohmmds-    -NMMMMMMMMM+
                                  `+dNNmy- `+yhhs:   `ohmmds-            sMMMMMMMMMMd
                                  hMMMMMMM-         -NMMMMMMMs           :MMMMMMMMMMo
                                  dMMMMMMM:         yMMMMMMMMM`           :dMMMMMMm+
                                  .hMMMMm+          :MMMMMMMMy              .:++/.
                                    `--.             -ymMMNh/
*/
#define END cout << "\nEnding\n"; exit(0);
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;

const int N = 4e1;
map<pair<int, int>, int> Q;
int n, a, b, A[N], B[N];

void dfs(int act = 0, int actA = 0, int actB = 0) {
    if (act == n / 2) {
        int cnt = min((a? actA / a : 0), actB / b);
        Q[{ actA - cnt * a, actB - cnt * b }]++;
        return;
    }
    dfs(act + 1, actA, actB);
    dfs(act + 1, actA + A[act], actB + B[act]);
}

ll res = 0;

void get(int act = n / 2, int actA = 0, int actB = 0) {
    if (act == n) {
        int cnt = min((a? actA / a : 0), actB / b);
        actA -= cnt * a;
        actB -= cnt * b;
        if (actA >= a || actB >= b) {
            return;
        }
        res += Q[{ (a? (a - actA) % a : 0), (b - actB) % b }];
        return;
    }
    get(act + 1, actA, actB);
    get(act + 1, A[act] + actA, B[act] + actB);
}

int main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    cin >> n >> a >> b;
    int cnt = 1;
    for (int i = 0; i < n; ++i) {
        cin >> A[i] >> B[i];
        cnt <<= A[i] == 0;
    }
    if (a == 0) {
        cout << cnt - 1 << "\n";
        return 0;
    }
    dfs();
    get();
    cout << res - 1 << "\n";

    return 0;
}