def METHOD_NAME(u, t):
    """Decode field elements (u, t) to an X coordinate on the curve."""
    if u == 0:
        u = FE(1)
    if t == 0:
        t = FE(1)
    if u**3 + t**2 + 7 == 0:
        t = 2 * t
    X = (u**3 + 7 - t**2) / (2 * t)
    Y = (X + t) / (MINUS_3_SQRT * u)
    for x in (u + 4 * Y**2, (-X / Y - u) / 2, (X / Y - u) / 2):
        if GE.is_valid_x(x):
            return x
    assert False