xs = [ (120, 50), (80, 75), (150, 100) ]
def solve(lst):
    n = len(lst)
    rem = set()
    for i in range(n):
        for j in range(n):
            if i != j and all(x <= y for x, y in zip(lst[i], lst[j])) and any(x < y for x, y in zip(lst[i], lst[j])):
                rem.add(i)
                break
    return set(lst) - set([lst[x] for x in rem])

r = solve(xs)
print(r)