The input contains a single integer *a* (1 ≤ *a* ≤ 64).

Output a single integer.
The input contains a single integer *a* (1 ≤ *a* ≤ 64).
a = int(input())
for i in range(1, 64):
    if a < i ** 2:
        print(i - 1)
        break
else:
    print(64)
