You are given natural number X. Find such maximum integer number that it square is not greater than X.
Input file contains number X (1≤X≤10^1000).
Write answer in output file.
16
4
if __name__ == '__main__':
n = int(input())
x = n
y = (x + 1) // 2
while y < x:
x = y
y = (x + n // x) // 2
print(x)