#include <bits/stdc++.h>

#define f first
#define s second
#define pb push_back
#define mp make_pair

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;

const int N = 3000500, inf = 1e9, mod = 998244353;
const ll INF = 1e18;

int sum(int a, int b) {
    a += b;
    if (a >= mod)
        a -= mod;
    return a;
}

int sub(int a, int b) {
    a -= b;
    if (a < 0)
        a += mod;
    return a;
}

int mult(int a, int b) {
    return 1ll * a * b % mod;
}

int bp(int a, int b) {
    int res = 1;
    while (b) {
        if (b & 1)
            res = mult(res, a);
        a = mult(a, a);
        b >>= 1;
    }
    return res;
}

int inv(int x) {
    return bp(x, mod - 2);
}

int d[N];

void solve() {
    int a, b;
    char c;
    cin >> a >> c >> b;
    for (int i = 1; i <= 1000000; i++) {
        if (i % b != 0)
            continue;
        int n = i;
        ll sd = 1ll * a * n / b;
        if (sd < n - 1)
            continue;
        if (sd > 1ll * n * (n - 1) / 2)
            continue;
        d[1] = 0;
        for (int j = 2; j <= n; j++) {
            d[j] = 1;
            sd--;
        }
        for (int j = 2; j <= n; j++) {
            ll can = d[j - 1] + 1 - d[j];
            ll need = sd;
            ll x = min(can, need);
            d[j] += x;
            sd -= x;
        }
        cout << n << " " << n - 1 << endl;
        for (int j = 2; j <= n; j++)
            cout << d[j] << " " << j << "\n";
        return;
    }
    cout << "impossible\n";
}

int main() {
#ifdef DEBUG
    freopen("input.txt", "r", stdin);
#endif
    ios_base::sync_with_stdio(false);
    int t = 1;
//    cin >> t;
    for (int i = 1; i <= t; i++) {
//        cout << "Case #" << i << endl;
        solve();
    }
}