import sys
input = sys.stdin.readline

T,x,y,z,w=list(map(int,input().split()))

dis=abs(x-z)+abs(y-w)

OK=0
NG=T

while NG>OK+1:
    mid=(OK+NG)//2

    print("?",mid,flush=True)

    retx,rety=list(map(int,input().split()))

    nowdis=abs(x-retx)+abs(y-rety)

    if nowdis*2<dis:
        OK=mid
    else:
        NG=mid

print("!",OK,flush=True)