function solve() {
    let nextBtn = document.getElementsByTagName("button")[0];
    let cancelBtn = document.getElementsByTagName("button")[1];
    cancelBtn.addEventListener("click", function(){
        document.getElementsByTagName("section")[0].style.display = "none";
    });

    let firstStepDiv = document.getElementById("firstStep");
    let secondStepDiv = document.getElementById("secondStep");
    let thirdStepDiv = document.getElementById("thirdStep");

    let licenseBtns = document.getElementsByName("license");
                
    for(i=0; i<licenseBtns.length; i++){

        let currentBtn = licenseBtns[i];

            licenseBtns[i].addEventListener("click", function(){
                
            currentBtn.setAttribute("checked", "");

                
                for(index=0; index<licenseBtns.length; index++){
                    if(licenseBtns[index] != currentBtn){
                        licenseBtns[index].removeAttribute("checked");
                    }
                }
              
        });   
    }

        nextBtn.addEventListener("click", function(){
            
            if(firstStepDiv.display != "block" && secondStepDiv.display != "block" && thirdStepDiv.display != "block"){
               
                document.getElementById("content").style.backgroundImage = "url()";
                firstStepDiv.style.display = "block";

            }

            if(firstStepDiv.display != "none" && secondStepDiv.display != "block" && thirdStepDiv.display != "block"){
                
                for(i=0; i<licenseBtns.length; i++){
                    if(licenseBtns[i].hasAttribute("checked") && licenseBtns[i].value == "agree"){
                            firstStepDiv.style.display = "none";
                            secondStepDiv.style.display = "block";
                            nextBtn.style.display = "none";
                    }
                }

            }

            if(firstStepDiv.display != "block" && secondStepDiv.display != "none" && thirdStepDiv.display != "block"){
               
                setTimeout(function(){

                    nextBtn.style.display = "inline";
                    
                    nextBtn.addEventListener("click", function(){
                        secondStepDiv.style.display = "none";
                        thirdStepDiv.style.display = "block";
                    })

                }, 3000);

            }

        });
}