Cod sursa(job #478239)
#include <cstdio>
int n;
int mod(int x)
{
if (x > n) x -= n;
return x;
}
int main()
{
freopen("tije.in", "r", stdin);
freopen("tije.out", "w", stdout);
scanf("%d", &n);
if (n == 2)
{
printf("1 3\n2 1\n3 2");
return 0;
}
for (int i = n - 1; i >= 1; --i)
for (int j = 1; j <= n; ++j)
{
int wh = mod(j + (n - i));
for (int k = 1; k <= i; ++k)
printf("%d %d\n", j, n + 1);
printf("%d %d\n", wh, j);
printf("%d %d\n", n + 1, wh);
for (int k = 1; k < i; ++k)
printf("%d %d\n", n + 1, j);
}
}