#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define re read()
#define INF 9223372036854775800
#define fr(i, x, y) for(int i = x, p = y; i <= p; ++i) 
#define rp(i, x, y) for(int i = x, p = y; i >= p; --i)
#define Timeok ((double)clock() / CLOCKS_PER_SEC < MAX_TIME)
const double MAX_TIME = 1.0 - 0.0032;

inline ll read()
{
   ll x = 0, f = 0;
   char ch = getchar();
   while (!isdigit(ch))
      f |= (ch == '-'), ch = getchar();
   while (isdigit(ch))
      x = (x << 1) + (x << 3) + (ch ^= 48), ch = getchar();
   return f ? -x : x;
}

void write(ll x)
{
   if (x < 0)
      putchar('-'), x = -x;
   if (x > 9)
      write(x / 10);
   putchar(x % 10 + 48);
}

inline void W(ll x, char ch)
{
    write(x);
    putchar(ch);
}

/*------------C-O-D-E------------*/

const int N = 1e7 + 4;
ll n, m, T;

ll v[N];
int mp[N];

int main()
{
    ll a, b, na, nb;
    scanf("%lld/%lld", &a, &b);
    na = a, nb = b;

    if(a < b-1)
    {
        puts("impossible");
        return 0;
    }

    while(1)
    {
        ll l = b * (b-1) / 2;
        if(a <= l) break;
        a += na, b += nb;
    }


    // W(a, '/'); W(b, '\n');
    n = b-1;
    fr(i,1,n) v[i] = 1;
    ll sum = n;
    fr(i,2,n)
    {
        fr(j, i, n)
        {
            if(sum == a) break;
            ++sum;
            v[j] = i;
        }
        if(sum == a) break;
    }

    // fr(i,1,n) cout<<v[i]<<' ';
    W(b, ' '); W(b-1, '\n');
    fr(i,1,n)
    {
        int opt = i+1;
        int pre;
        if(mp[v[i]] == 0)
        {
            mp[v[i]] = i;
            pre = i;
        }
        else
        {
            pre = mp[v[i]];
        }
        W(pre, ' '); W(opt, '\n');
    }
    return 0;
}