Untitled

import os
os.system

def clear():
    if os.name == 'nt':
        os.system('cls')
    elif os.name == 'posix':
        os.system('clear')
def menu():
    print(': THREE DAY PLANNER :')
    print('---------------------')
    print('    WORKOUT GOALS!   ')
    print('  ONE DAY AT A TIME. ')
    print('---------------------')

def table():
    print('TODAY: Run 5 km')
    print('TOMORROW: Lift 10 kg')
    print('LATER: Cycle 30 km')
    print('---------------------')

def operations():
    print('n | Next day')
    print('c | Change goal')
    print('e | Exit program')
    print('---------------------')

def next_day():
    print('TODAY: Lift 10 kg')
    print('TOMORROW: Cycle 30 km')
    print('LATER: ')
    print('---------------------')


while True:
    menu()
    table()
    operations()
    operation = input('operation > ')
    if operation =='e':
        exit()
    elif operation == 'n':