x and y game

import math

n = int(input())
arr = list(map(int, input().split(" ")))
x = 0
y = 0
st = [[0,0]] * int((math.factorial(n))/4)
for i in range(n):
    for j in range(i+1,n):
        # if i + j == 0
        # print(arr[i],i , arr[j],j)
        print([i - j])
        
print(st)