Problems

# Vector length

Find the length of the vector.

#### Input

Four integers x1, y1, x2, y2 - the coordinates of the beginning and end of the vector, respectively. All input data do not exceed 10000 by absolute value.

#### Output

Print the length of the given vector with 6 digits after the decimal point.

Time limit 1 second
Memory limit 128 MiB
Input example #1
1 1 2 2

Output example #1
1.414214