class MyCalendarThree {
    public static void main(String[] args) {
        MyCalendarThree myCalendarThree = new MyCalendarThree();
        System.out.println( myCalendarThree.book(10,20) );
        System.out.println(myCalendarThree.book(50,60));
        System.out.println(myCalendarThree.book(10,40));
        System.out.println(myCalendarThree.book(
 
5,15));
        System.out.println(myCalendarThree.book(5,10));
        System.out.println(myCalendarThree.book(25,55));
    }
    class Seg{
        int cl,cr;
        Seg left,right;
        int cnt;
        int max;

        public Seg(int l,int r){
            this.cl = l;
            this.cr = r;
            
 
this.cnt = 0;
            this.max = 0;
        }

        public void pushdown(){
            int mid = (cl+cr)/2;
            if( this.left == null){
                this.left = new Seg(cl,mid);
            }
            if(this.right == null){
                this.right = new Seg(mid+1,cr);
            }
            
 
if( this.cnt == 0){
                return;
            }
            this.left.max += this.cnt;
            this.right.max += this.cnt;
            this.left.cnt += this.cnt;
            this.right.cnt += this.cnt;
            this.cnt = 0;
        }
        public void add(int l,int r){
            if(cl == l &&cr == r){
                this.cnt++;
                this.max++;
                return;
            }
            pushdown();
            int mid = (cl+cr)/2;
            if( r<=mid){
                this.left.add(l,r);
            }else{
                if(l>mid){
                    this.right.add(l,r);
                }else{
                    this.left.add(l,mid);
                    this.right.add(mid+1,r);
                }
            }
            //pushup 啥也不做
            pushup();
        }

        public void pushup(){
            this.max = Math.max(this.left.max,this.right.max);
        }

        public int search(int l,int r){
            if(cl ==l &&cr == r){
                return  this.max;
            }
            pushdown();
            int mid = (cl+cr)/2;
            int ans ;
            if(r<=mid){
                ans = this.left.search(l,r);
            }else{
                if(l>mid){
                    ans = this.right.search(l,r);
                }else{
                    int val1 = this.left.search(l,mid);
                    int val2 = this.right.search(mid+1,r);
                    ans = Math.max(val1,val2);
                }
            }
            pushup();
            return ans;
        }
    }
    Seg seg;
    int k ;
    public MyCalendarThree() {
        seg = new Seg(0,1000000000);
        k = 0;
    }

    public int book(int start, int end) {

        seg.add(start,end-1);
         int val = seg.search(start,end-1);
        if(val > k){
            k = val;
        }
        return k;
    }
}

/**
 * Your MyCalendarThree object will be instantiated and called as such:
 * MyCalendarThree obj = new MyCalendarThree();
 * int param_1 = obj.book(start,end);
 */