T, x0, y0, x1, y1 = map(int, input().split())

t0 = 0
t1 = T

while t1 - t0 > 1:

    m = (t0 + t1) // 2 

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

    x,y = map(int, input().split())

    d0 = abs(x-x0) + abs(y-y0)
    d1 = abs(x-x1) + abs(y-y1)

    if d0 <= d1:
        t0 = m
    else:
        t1 = m

print("!",t0)