X t c

X t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t cX t c