scientific_comp_projects/CODE/[python]kattis/trivial/stopwatch.py

number = int(input())
if number%2!=0:
    for i in range(number):
        a = input()
    print('still running')
else:
    time = 0
    for i in range(int(number/2)):
        a = int(input())
        b = int(input())
        time = time +(b-a) 

    print(time)