T,a,b,c,d=map(int,input().split())
l=0
r=T
count=0
while True:
  m=(l+r)//2
  count+=1
  if count>90:
    if (a+b-(c+d))%2==1:
      print('!',l,flush=True)
    else:
      print('!',l+1,flush=True)
    exit()
  print('?',m,flush=True)
  x,y=map(int,input().split())
  s0=abs(x-a)+abs(y-b)
  s1=abs(x-c)+abs(y-d)
  if s0==s1:
    print('!',m,flush=True)
    exit()
  if s0<s1:
    l=m
  else:
    r=m