def Question(X):
    print("? {}".format(X),flush=True)
    return input()=="safe"

def Answer(X):
    print("! {}".format(X),flush=True)
    exit()
#==============================================
L,R=0,1001

while R-L>1:
    C=L+(R-L)//2
    p=Question(C)
    if not p:
        q=Question(C+1)
        if q:
            L=C
        else:
            R=C
    else:
        L=C
Answer(L)