dict1 = {'maths' : 23 ,'science':22, 'english' : 20 , 'history' : 10}
print('The subjects in the dict1 are')
print(dict1.keys())
print('The marks scored by students are')
print(dict1.values())
del dict1['history']
print('The values in dictionary after deleting lowest mark is')
print(dict1)
dict1['english'] = 24
print('The values of dictionary after english mark is changed')
print(dict1)
var = dict1.get('history','History is not present in dictionary')
print(var)