#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define lll _int128
#define ull unsigned long long
#define PB push_back
#define fi first
#define se second
#define _int _int128
#define fr(i,a,b) for(int i = a ; i <= b ; i++)
#define rp(i,a,b) for(int i = a ; i >= b ; i--)
#define frp(i,a,b) for(int i = 1 ; i < b ; i ++ )
#define re read()
#define db double
#define ld long double
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
const int inf = 0x3f3f3f3f;
const ll N = 2e5+10;
const ll mod = 1e9+7;
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;
}
inline 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);
}
ll aa[N];
void slove()
{
	ll a,b;
	char c;
	cin>>a>>c>>b;
	if(a < b)
	{
		if(a == b - 1)
		{
			cout<<b<<" "<<a<<endl;
			fr(i,2,b)
			{
				cout<<1<<" "<<i<<endl;
			}
			return;
		}
		cout<<"impossible"<<endl;
		return;
	}
	ll k = a/b;
	ll s = 0;
	fr(i,0,2*k)
	{
		if(i == k )
		{
			if(b == 1)
			{
				aa[i] = 4*k;
				s += (4*k)*i;
			}
			else
			{
				aa[i] = 2*k*(b-1) + k*b; s += (3*k*b-2*k)*i;
			} 
			continue;
		}
		s += i;
		aa[i] = 1;
	}
	ll sum;
	if(b == 1)
	{
		sum = 6*k;
	}
	else sum = 3*k*b;			//总点
	ll tt = a*(sum/b);
	ll cha = s - a*(sum/b);
	cha = abs(cha);
//	cout<<cha<<" "<<s<<tt<<endl;
	aa[k] -= cha;
	aa[k+1]+=cha;
	ll cn;
	cout<<sum<<" "<<sum-1<<endl;
	fr(i,1,2*k)
	{
		cout<<i<<" "<<i+1<<endl;
		cn = i + 2;
	}
	fr(i,1,aa[k]  - 1)
	{
		cout<<k<<" "<<cn++<<endl;
	}
	fr(i,1,aa[k+1]-1)
	{
		cout<<k+1<<" "<<cn++<<endl;
	}
}
 
int main()
{
//	freopen("input.txt","r",stdin);
//	freopen("output.txt","w",stdout);
    int tcase = 1;
  //	cin>>tcase;
    while(tcase--)
    {
    	slove();
	}
    return 0;
}