.slider {
	float:left;
	width: 50%;
	margin: auto;
	overflow: hidden;
	height: 400px;
}

.slider ul {
	display: flex;
	padding: 0;
	width: 400%;

	animation: cambio 20s infinite;
	animation-direction: alternate;
}

.slider li {
	list-style: none;
	width: 100%;
}

.slider img {
	width: 100%;
	height: 400px;
}

@keyframes cambio {
	0% { margin-left: 0; }
	20%{ margin-left: 0; }
	
	25%{ margin-left: -100%; }
	45%{ margin-left: -100%; }

	50%{ margin-left: -200%; }
	70%{ margin-left: -200%; }

	75%{ margin-left: -300%; }
	100%{ margin-left: -300%; }

}
.menuPrincipal{
	float:left;
  	width:20%;
  	padding:0 20px;
}