def Exp2(x):
    """Use reduction formula to evaluate very large Exponentials quickly."""
    prec = x.getprec()
    x = gmpy.mpf(x,prec+1)
    i = 1
    sign = 0
    if x < 0:
        sign = 1
        x = -x
    l = bit_length(gmpy.mpz(x))
    print l
    x /= gmpy.mpz(1) << l
    y = gmpy.mpf(0,prec+1)
    t = gmpy.mpf(1,prec+1)
    oy = y
    while(1):
        y += t
        t *= x
        t /= i
        if (oy - y) == 0:
            break
        oy = y
        i += 1
    for i in range(l):
        y*=y
    if(sign):
        y = 1/y
    return gmpy.mpf(y, prec)