function utopianTree(n) {
    
    var height = 1
    var double_hight_growth = true
    
    for (var i = 1; i <=n ;i++){
        
        if (double_hight_growth){
            
            double_hight_growth = false
            height =  2 * height
            
        }
        else{
            
            double_hight_growth = true
            height = height + 1
        }
        
        
    }
    return height

}