from sys import stdin,setrecursionlimit#,set_int_max_str_digits
#import pypyjit
#pypyjit.set_param('max_unroll_recursion=-1')
setrecursionlimit(20000000) # これこどふぉだと無理
#set_int_max_str_digits(200010)
mod = 998244353 
ii = lambda :int(stdin.readline())
mi = lambda :map(int,stdin.readline().split())
li = lambda :list(mi())
gmi = lambda :map(lambda x: int(x) - 1, stdin.readline().split())
gi = lambda :list(map(lambda x: 0 if x == "." else 1,input())) # グリッド入力受け取り
py = lambda :print("Yes")
pn = lambda :print("No")
pf = lambda :print("First") 
ps = lambda :print("Second")
vec = [(1,0),(-1,0),(0,-1),(0,1)]
vec1 = [(1,0),(1,1),(0,1),(-1,1),(-1,0),(-1,-1),(0,-1),(1,-1)] #8方向
inf = 10**18


n = ii() 

a = [list(map(float,stdin.readline().split())) for _ in range(n)]
b = [list(map(float,stdin.readline().split())) for _ in range(n)]


x2,y2 = 0,0
for x,y in a:
    if x2 < x:
        x2 = x 
        y2 = y 
    elif x2 == x and y2 < y:
        y2 = y 




x4,y4 = 0,0
for x,y in b:
    
    if x4 < x:
        x4 = x 
        y4 = y 
    elif x4 == x and y4 < y:
        y4 = y 


if x4 == y4 == 0.0:
    print(0) 
    exit() 

if x4 != 0:
    print(x4/x2) 
else:
    print(y4/y3)