Problem:
Distance

Write a program which calculates the distance between two points P1(x1, y1) and P2(x2, y2).

Input

Four real numbers x1, y1, x2 and y2 are given in a line.

Output

Print the distance in real number. The output should not contain an absolute error greater than 10-4.

Sample Input

0 0 1 1

Sample Output

1.41421356

Solution in Python3 (judge verdict: Accepted)

import math
import copy
from copy import deepcopy
import sys
import fractions
# import numpy as np
from functools import reduce
# import statistics
import decimal
import heapq
import collections
import itertools
from operator import mul

sys.setrecursionlimit(100001)


# input = sys.stdin.readline
# sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

x1, y1, x2, y2 = map(float, input().split())

ans = pow(x1-x2, 2) + pow(y1-y2, 2)
ans = math.sqrt(ans)
print(ans)