# SQ3.py  computes a square root of a nonnegative int.
# input: a nonnegative int
# output: a nonnegative square root or an error message

import math

text = raw_input("Type an int: ")

if text.isdigit() :   # does text contain all digits?
    num = int(text)
    if num >= 0 :
        print math.sqrt(num)
else :
    print "bad input"

print  # blank line
raw_input("press Enter to finish")