#include <bits/stdc++.h>

#define endl '\n'
#define DEBUG_VAR(x) { cerr << "* "#x" = " << endl; }

using namespace std;
using LL = long long;

const int N = 1e6+5;

int a, b;
int cur_a, cur_b;

int c[N];

int main()
{
	// freopen("1.in", "r", stdin);
	ios::sync_with_stdio(false); cin.tie(nullptr);

	scanf("%d/%d", &a, &b);
	if(a < b-1) {
		cout << "impossible" << endl;
		return 0;
	}

	int cur_a = a, cur_b = b;
	while(cur_a > cur_b*(cur_b-1)/2) {
		cur_a += a;
		cur_b += b;
	}

	int cnt = 1, sum = 0;
	c[0] = 1;
	for(int i = 1; i < N && cnt < cur_b && sum < cur_a; i++) {
		if((cur_b-cnt)*i == cur_a-sum) {
			c[i] = cur_b-cnt;
			cnt = cur_b;
			sum = cur_a;
		} else if((cur_b-cnt-1)*(i+1)+i > cur_a-sum) {
			int x = 0;
			while(x <= cur_b-cnt && x*i+(cur_b-cnt-x)*(i+1) > cur_a-sum) 
				x++;
			c[i] = x;
			c[i+1] = cur_b-cnt-x;
			sum += c[i]*i+c[i+1]*(i+1);
			cnt = cur_b;
		} else {
			c[i] = 1;
			cnt++;
			sum += i;
		}
	}

	printf("%d %d\n", cur_b, cur_b-1);
	int idx = 1;
	int las = 1;
	for(int i = 1; i < N && c[i]; i++) {
		for(int j = 1; j <= c[i]; j++) {
			printf("%d %d\n", las, ++idx);
		}
		las = idx;
	}
	return 0;
}