from math import isqrt

def sqrt(n):
    d = len(str(isqrt(n)))
    a, b = 5 * n, 5
    step = 0
    while step < 10000:
        if a >= b:
            a, b = a - b, b + 10
        else:
            a, b = a * 100, (b // 10) * 100 + b % 10

        step += 1
    res = str(b)
    return f"{res[:d]}.{res[d:]}"

r = sqrt(2)
print(r)