Equilateral numbers

n = int(input())
def eqnum(k):
    if k % 2 == 1:
        return k*((k+1)//2)
    else:
        return (k//2)*(k+1)
def binsearch(n, k0, k1):
    mid = (k0 + k1) // 2
    e = eqnum(mid)
    # print(n, k0, k1, e)
    if e == n:
        return mid
    elif k0 >= k1:
        if e > n:
            return k1-1
        else:
            return k1
    elif e > n:
        return binsearch(n, k0, mid-1)
    else:
        return binsearch(n, mid+1, k1)

k = 10**13
c = 0
while(n):
    # print("here:",n,k)
    e = eqnum(k)
    if e <= n:
        c += 1
        n -= e
    else:
        k = binsearch(n,1,k)
print(c)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER