import sys,bisect,string,math,time,functools,random,fractions
from heapq import heappush,heappop,heapify
from collections import deque,defaultdict,Counter
from itertools import permutations,combinations,groupby
rep=range;R=range
def Golf():n,*t=map(int,open(0).read().split())
def I():return int(input())
def S_():return input()
def IS():return input().split()
def LS():return [i for i in input().split()]
def MI():return map(int,input().split())
def LI():return [int(i) for i in input().split()]
def LI_():return [int(i)-1 for i in input().split()]
def NI(n):return [int(input()) for i in range(n)]
def NI_(n):return [int(input())-1 for i in range(n)]
def StoLI():return [ord(i)-97 for i in input()]
def ItoS(n):return chr(n+97)
def LtoS(ls):return ''.join([chr(i+97) for i in ls])
def RA():return map(int,open(0).read().split())
def GI(V,E,ls=None,Directed=False,index=1):
    org_inp=[];g=[[] for i in range(V)]
    FromStdin=True if ls==None else False
    for i in range(E):
        if FromStdin:
            inp=LI()
            org_inp.append(inp)
        else:
            inp=ls[i]
        if len(inp)==2:
            a,b=inp;c=1
        else:
            a,b,c=inp
        if index==1:a-=1;b-=1
        aa=(a,c);bb=(b,c);g[a].append(bb)
        if not Directed:g[b].append(aa)
    return g,org_inp
def GGI(h,w,search=None,replacement_of_found='.',mp_def={'#':1,'.':0},boundary=1):
    #h,w,g,sg=GGI(h,w,search=['S','G'],replacement_of_found='.',mp_def={'#':1,'.':0},boundary=1) # sample usage
    mp=[boundary]*(w+2);found={}
    for i in R(h):
        s=input()
        for char in search:
            if char in s:
                found[char]=((i+1)*(w+2)+s.index(char)+1)
                mp_def[char]=mp_def[replacement_of_found]
        mp+=[boundary]+[mp_def[j] for j in s]+[boundary]
    mp+=[boundary]*(w+2)
    return h+2,w+2,mp,found
def TI(n):return GI(n,n-1)
def accum(ls):
    rt=[0]
    for i in ls:rt+=[rt[-1]+i]
    return rt
def bit_combination(n,base=2):
    rt=[]
    for tb in R(base**n):s=[tb//(base**bt)%base for bt in R(n)];rt+=[s]
    return rt
def gcd(x,y):
    if y==0:return x
    if x%y==0:return y
    while x%y!=0:x,y=y,x%y
    return y
def YN(x):print(['NO','YES'][x])
def Yn(x):print(['No','Yes'][x])
def show(*inp,end='\n'):
    if show_flg:print(*inp,end=end)

mo=10**9+7
inf=float('inf')
FourNb=[(-1,0),(1,0),(0,1),(0,-1)];EightNb=[(-1,0),(1,0),(0,1),(0,-1),(1,1),(-1,-1),(1,-1),(-1,1)];compas=dict(zip('WENS',FourNb));cursol=dict(zip('LRUD',FourNb))
l_alp=string.ascii_lowercase
#sys.setrecursionlimit(10**7)
read=sys.stdin.buffer.read;readline=sys.stdin.buffer.readline;input=lambda:sys.stdin.readline().rstrip()

########################################################################################################################################################################
# Binary Indexed Tree
# Bit.add(i,x)    : add x at i-th value
# Bit.sum(i)      : get sum up to i-th value
# Bit.l_bound(w)  : get lower bound of index where w can be inserted

class Bit:
    def __init__(self,n,init=None):
        self.size=n
        self.m=len(bin(self.size))-2
        self.arr=[0]*(2**self.m+1)
        if init!=None:
            for i in range(len(init)):
                self.add(i,init[i])
        
    def __str__(self):
        a=[self.sum(i+1)-self.sum(i) for i in range(self.size)]
        return str(a)
        
    def add(self,i,x):
        if i<0:return NotImplemented
        k=0
        while i<=self.size:
            k+=1
            self.arr[i]+=x
            i+=i&(-i)
        return
    
    def sum(self,i):
        if i<0:return NotImplemented
        rt=0
        while i>0:
            rt+=self.arr[i]
            i-=i&(-i)
        return rt
    
    def __getitem__(self,key):
        return self.sum(key+1)-self.sum(key)

    def __setitem__(self,key,value):
        self.add(key,value-self.sum(key+1)+self.sum(key))

    def l_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<self.size and self.arr[x+k]<w:
                w-=self.arr[x+k]
                x+=k
            k//=2
        return x+1
        
    def u_bound(self,w):
        if w<=0:
            return 0
        x=0
        k=2**self.m
        while k>0:
            if x+k<self.size and self.arr[x+k]<=w:
                w-=self.arr[x+k]
                x+=k
            k//=2
        return x+1
        
class Bit0(Bit):
    def add(self,j,x):
        super().add(j+1,x)
    def l_bound(self,w):
        return max(super().l_bound(w)-1,0)
    def u_bound(self,w):
        return max(super().u_bound(w)-1,0)

class Multiset(Bit0):
    def __init__(self,max_v):
        super().__init__(max_v)
    def insert(self,x):
        super().add(x,1)
    def find(self,x):
        return super().l_bound(super().sum(x))
    def __str__(self):
        return str(self.arr)

def compress(L):
    dc={v:i for i,v in enumerate(sorted(set(L)))}
    return [dc[i] for i in L]

show_flg=False
show_flg=True

ans=0

n=I()
d=90
c=[0]*d
p=[[]for i in range(d)]
for i in range(n):
    x,y=LI()
    k=y%18
    if k<9:
        z=k*10+x%10
    else:
        z=(k-9)*10+(x+5)%10
    c[z]+=1
    p[z]+=i+1,

tmp=c[0]
ans=0
for i in range(d):
    if tmp<c[i]:
        tmp=c[i]
        ans=i
print(tmp)
print(*p[ans])