# If I have X1,Y1 indicating one point in the plane, 
# and X2,Y2 another point, how far apart are they?
# Square root of the sum of the squares of the differences in x and differences in y.

def Distance():
    X1 = input("Enter X1 --- ")
    Y1 = input("Enter Y1 --- ")
    X2 = input("Enter X2 --- ")
    Y2 = input("Enter Y2 --- ")
    DeltaX = X2 - X1
    DeltaY = Y2 - Y1
    Sum = DeltaX*DeltaX + DeltaY*DeltaY
    Result = sqrt(Sum)
    print Result
    return