import sys
import math
import bisect
from heapq import heapify, heappop, heappush
from collections import deque, defaultdict, Counter
from functools import lru_cache
from itertools import accumulate, combinations, permutations, product

sys.setrecursionlimit(1000000)
MOD = 10 ** 9 + 7
MOD99 = 998244353

input = lambda: sys.stdin.readline().strip()
NI = lambda: int(input())
NMI = lambda: map(int, input().split())
NLI = lambda: list(NMI())
SI = lambda: input()
SMI = lambda: input().split()
SLI = lambda: list(SMI())
EI = lambda m: [NLI() for _ in range(m)]


def score(a, b, x):
    v1 = abs(5 * 10**17 - a)
    v2 = abs(5 * 10**17 - b)
    if max(v1, v2) > 0:
        return int(2000000 - 100000 * math.log10(max(v1, v2)+1))
    else:
        return 2000050 - x


def answer(ans):
    print(len(ans))
    for i, j in ans:
        print(i+1, j+1)


def main():
    N = NI()
    AB = EI(N)

    ans = []
    # 0と何かだけで貪欲
    for qi in range(50):
        a0, b0 = AB[0]
        s = score(a0, b0, qi)
        best_s = s
        best_v = 1
        for v in range(1, N):
            av, bv = AB[v]
            na, nb = (a0+av) // 2, (b0+bv) // 2
            ns = score(na, nb, qi+1)

            if ns > best_s:
                best_s = ns
                best_v = v

        if best_s > s:
            av, bv = AB[best_v]
            na, nb = (a0 + av) // 2, (b0 + bv) // 2
            AB[0] = [na, nb]
            AB[best_v] = [na, nb]
            ans.append([0, best_v])
        else:
            break

    answer(ans)



if __name__ == "__main__":
    main()