.slider
{
  float: left;
  width: 100%;
  margin:auto;
  overflow: hidden;
  position: relative;
  margin-bottom: 0px;
}
.slider ul
{
  display: flex;
  padding: 0px;
  width: 500%;
  animation: cambio 20s infinite alternate;
}
.slider li
{
  width: 100%
  list-style:none;
}
.slider img
{
  width: 100%;
}
@keyframes cambio {
  0% {margin-left: 0;}
  15% {margin-left: 0;}

  20% {margin-left: -130%;}
  40% {margin-left: -130%;}

  45% {margin-left: -250%;}
  60% {margin-left: -250%;}

  65% {margin-left: -380%}
  80% {margin-left: -380%;}

}