st=[""]*100
top=-1
flag=True
s=input()
for i in range(len(s)):
    if s[i]=="(" or s[i]=="[" or s[i]=="{":
        top+=1
        st[top]=s[i]
    elif s[i]==")" and st[top]=="(" or s[i]=="]" and st[top]=="[" or s[i]=="}" and st[top]=="{":
        top-=1
    else:
        flag=False
        break
if top==-1 and flag:
    print('OK')
else:
    print("Wrong")