import sys
from math import sqrt, pi, sin, factorial
BLANK = " "
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
n = int(input())
p(n - 1)
for i in range(n - 1):
p(0, i)
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
input()
ret = solve()