Binary search

#find if there is such element in the list
#list ISN'T sorted

n = int(input())
a = list(map(int, input().split()))
x = int(input())

a.sort()

#we consider elements in positions [l, r) -- a[l], a[l + 1], ..., a[r - 1].

l = 0
r = n
while l < r - 1: #there is more than one element
    m = (l + r) // 2 #look at the value in the middle
    if a[m] <= x:
        l = m
    else:
        r = m

if a[l] == x:
    print('There is')
else:
    print ('There isn\'t')