Note to self: GlobeX Cup '19 Senior was a mistake... (i wonder how much my rating will drop?)

Fast Java IO:

static class Reader { 
        final private int BUFFER_SIZE = 1 << 16; 
        private DataInputStream din; 
        private byte[] buffer; 
        private int bufferPointer, bytesRead; 

        public Reader() { 
            din = new DataInputStream(System.in); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 

        public Reader(String file_name) throws IOException { 
            din = new DataInputStream(new FileInputStream(file_name)); 
            buffer = new byte[BUFFER_SIZE]; 
            bufferPointer = bytesRead = 0; 
        } 

        public String read() throws IOException {
            byte[] ret = new byte[64];
            int idx = 0;
            byte c = Read();
            while (c <= ' ') {
                c = Read();
            }
            do {
                ret[idx++] = c;
                c = Read();
            } while (c != -1 && c != ' ' && c != '\n' && c != '\r');
            return new String(ret, 0, idx);
        }

        public String readLine() throws IOException { 
            byte[] buf = new byte[64];
            int cnt = 0, c; 
            while ((c = Read()) != -1) { 
                if (c == '\n') 
                    break; 
                buf[cnt++] = (byte) c; 
            } 
            return new String(buf, 0, cnt); 
        } 

        public int nextInt() throws IOException { 
            int ret = 0; 
            byte c = Read(); 
            while (c <= ' ') 
                c = Read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = Read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            }  while ((c = Read()) >= '0' && c <= '9'); 
            return neg ? -ret : ret;
        } 

        public long nextLong() throws IOException { 
            long ret = 0; 
            byte c = Read(); 
            while (c <= ' ') 
                c = Read(); 
            boolean neg = (c == '-'); 
            if (neg) 
                c = Read(); 
            do { 
                ret = ret * 10 + c - '0'; 
            } while ((c = Read()) >= '0' && c <= '9'); 
            return neg ? -ret : ret;
        } 

        public double nextDouble() throws IOException {
            double ret = 0, div = 1; 
            byte c = Read(); 
            while (c <= ' ') 
                c = Read(); 

            boolean neg = (c == '-'); 
            if (neg) 
                c = Read(); 

            do { 
                ret = ret * 10 + c - '0'; 
            } while ((c = Read()) >= '0' && c <= '9'); 

            if (c == '.')
                while ((c = Read()) >= '0' && c <= '9')
                    ret += (c - '0') / (div *= 10); 

            return neg ? -ret : ret;
        } 

        private void fillBuffer() throws IOException {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
            if (bytesRead == -1) 
                buffer[0] = -1; 
        } 

        private byte Read() throws IOException {
            if (bufferPointer == bytesRead) 
                fillBuffer(); 
            return buffer[bufferPointer++]; 
        } 

        public void close() throws IOException { 
            if (din == null) 
                return; 
            din.close(); 
        } 
    }