Equilateral numbers

def s(a):
    k = 1
    b = 1 + 8 * a
    while k ** 2 < b:
        k += 1
    return k ** 2 == b


n = int(input())
k = False
if s(n):
    print(1)
else:
    a = 1
    while (a * ( a - 1)) // 2 < n:
        if s(n - 2):
            k = True
            break
        a += 1
    if k:
        print(2)
    else:
        print(3)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: TIME LIMIT EXCEEDED

Test 12

Verdict: TIME LIMIT EXCEEDED