input = """
"""

output = """
{p_xx(0,0), p_xx(1,1), p_xx(2,2), p_xx(3,3), p_xx(4,4), p_xx(5,5), p_xx(6,6), px_x(0,0), px_x(1,1), px_x(2,2), px_x(3,3), px_x(4,4), px_x(5,5), px_x(6,6), pxx4(2,2), pxx_(0,0), pxx_(1,1), pxx_(2,2), pxx_(3,3)}
"""
