Ac7jnRGtg9AlOc3KdO5lugo_WjOiYC6KyJW-zGPAWjk code

Hi, on my page http://www.koijazierka.sk I found the strange code Ac7jnRGtg9AlOc3KdO5lugo_WjOiYC6KyJW-zGPAWjk on left top site. How am I to get there?