import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(1000005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# md = 10**9+7
md = 998244353

def outer(i, j, k):
    x, y = xy[i]
    p, q = xy[j]
    s, t = xy[k]
    return (s-x)*(q-y)-(t-y)*(p-x)

n = II()
xy = LLI(n)
ii = sorted(range(n), key=lambda i: xy[i][0])
fin = [0]*n

ans = []
for i in ii:
    if fin[i]: continue
    j = 0
    while j < n and fin[j] or j == i: j += 1
    if j == n: break
    for k in range(n):
        if fin[k]: continue
        if outer(i, j, k) > 0: j = k
    ans.append((i+1, j+1))
    fin[i] = 1
    fin[j] = 1

print(len(ans))
for i, j in ans: print(i, j)