소스 코드 제출

'''
a=input()
b=[0 for i in range(26)]
for i in range(len(a)):
    x=ord(a[i])
    if 97<=x<=122:
        b[x-97]=b[x-97]+1
for i in range(26):
    print(chr(97+i),':',b[i],sep='')
s=input()
for i in range(len(s)):
    if s[i]=='t':
        print(i+1,end=' ')
a=input()
b=list(a)
x=int(a)
b.reverse()
a=''.join(b)
y=int(a)
c=str(x+y)
d=list(c)
z=int(c)
d.reverse()
c=''.join(d)
w=int(c)
print('YES' if z==w else 'NO')
a=input()
b=list(a)
b.reverse()
a=''.join(b)
print(a)
a=input()
b=[]
for i in range(len(a)):
    if a[i]=='0' or a[i]=='1' or a[i]=='2':
        b.append(a[i])
    elif a[i]=='A' or a[i]=='B':
        for j in range(ord(a[i])-64):
            b.pop()
    else:
        b.clear()
a=''.join(b)
print(a)
a=input()
b=input()
c=input()
if a[-1]==b[0] and b[-1]==c[0] and c[-1]==a[0]:
    print('good')
else:
    print('bad')
'''
a,b=map(int,input().split("x"))
x=-b/a
print(format(x,".2f"))