import sys
import math

import io
import sys
import random
TARGET = 500000000000000000
random.seed(18)

def cal_score(v1, v2, isDisplay = False):
    error1 = abs(v1-TARGET)
    error2 = abs(v2-TARGET)
    sa = max(error1,error2)
    #score = int(2 * 10**6 - 10**5 * math.log10(sa +1.0))    
    score = (int)(2000000.0 - 100000.0 * math.log10(1.0 * max(error1, error2) + 1.0))

    if isDisplay:
        print(TARGET,v1,v2)
        print(error1,error2,score)

    return score

def cal_temp_score(v1, v2, isDisplay = False):
    error1 = abs(v1-TARGET)
    error2 = abs(v2-TARGET)

    score = - error1 - error2
    if isDisplay:
        print(error1,error2,score)
    return score    

def cal_ave(A,B, i,j):
    aveA,aveB = (A[i] + A[j])//2, (B[i] + B[j])//2
#    print(i,j,A[i],A[j],aveA,B[i],B[j],aveB)
    A[i] = aveA
    A[j] = aveA

    B[i] = aveB
    B[j] = aveB  

#    print("after",  i,j,A[i],A[j],aveA,B[i],B[j],aveB)


def save(A, B, i,j):
    return (i,j,A[i],B[i],A[j],B[j])

def restore(A, B, save):
    i,j = save[0], save[1]
    A[i],B[i],A[j],B[j] = save[2],save[3],save[4],save[5]

def main():
    args = sys.argv
    debug = False

    if len(args) >= 2:
        debug = True

    sys.setrecursionlimit(10000000)

    #H=int(input())

    #A=list(map(int,input().split()))

    #A,B=map(int,input().split())
    #A,B=input().split()

    #B =  [list(map(int,input().split())) for _ in range(N)]


    
    # 入力
    N = int(input())
    A = [0] * (N +1)
    B = [0] * (N +1)
    for i in range(1,N+1):
        A[i], B[i] = map(int, input().split())

    MAX_SOUSA = 50
    TEMP_ITER = -1

    # 出力
    print(MAX_SOUSA)

    it = 0
    for it in range(MAX_SOUSA):
        now_score = cal_score(A[1],B[1])

        kouho = (1,1)
        for i in range(2, N + 1):
            save_info = save(A,B,1,i)
            cal_ave(A,B,1,i)

            score = cal_score(A[1],B[1])
            restore(A,B,save_info)

            if now_score < score:
                kouho = (1,i)
                now_score = score                

        if kouho[1] ==1:
            kouho_list = []

            for k in range(2, N+1):
                for l in range(2, N+1):
                    if l >= k:
                        continue
                    score = cal_score(A[k],B[l])
                    save_info = save(A,B,k,l)
                    cal_ave(A,B,k,l)
                    after_score = cal_score(A[k],B[l])
                    if after_score > score:
                        kouho_list.append((after_score,(k,l)))
                    restore(A,B,save_info)

            kouho_list.sort(reverse=True)

            kouho = kouho_list[0][1]

        cal_ave(A,B,kouho[0],kouho[1])
        print(f"{kouho[0]} {kouho[1]}")    

        if debug:
            print(it, "score")
            cal_score(A[1],B[1], True)

if __name__ == "__main__":
    main()