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

Output a single integer.
The input contains a single integer *a* (1 ≤ *a* ≤ 64).
l=input()
l=int(l)
for i in range(1,9):
    if i*i>=l and (i-1)*(i-1)<l:
        print(i-1)
        break