시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 1024 MB 25 20 17 89.474%

## 문제

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.

## 입력

The first line of input contains a single integer $N$ ($1 \leq N \leq 1\,000$), 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.

## 출력

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.

## 예제 입력 1

2
7
11


## 예제 출력 1

4


## 예제 입력 2

5
2
5
9
10
17


## 예제 출력 2

still running


## 예제 입력 3

4
0
2
104
117


## 예제 출력 3

15


## 출처

• 문제를 만든 사람: Zachary Friggstad