Robin just received a stopwatch from her grandfather. Robin’s stopwatch has a single button. Pressing the button alternates between stopping and starting the stopwatch’s timer. When the timer is on, the displayed time increases by 1 every second.

Initially the stopwatch is stopped and the timer reads 0 seconds. Given a sequence of times that the stopwatch button is pressed, determine what the stopwatch’s timer displays.

-----Input-----
The first line of input contains a single integer $N$ ($1 \leq N \leq 1000$), which is the number of times the stopwatch was pressed.

The next $N$ lines describe the times the stopwatch’s button was pressed in increasing order. Each line contains a single integer $t$ ($0 \leq t \leq 10^6$), which is the time the button was pressed. No two button presses happen on the same second.

-----Output-----
Display still running if the stopwatch’s timer is still running after all button presses were made. Otherwise display the number of seconds displayed on the stopwatch’s timer.

-----Examples-----
Sample Input 1:
2
7
11
Sample Output 1:
4

Sample Input 2:
5
2
5
9
10
17
Sample Output 2:
still running

Difficulty: introductory

Starter code:

Solutions: