with open('D:\python1\PAMPAM.txt',encoding='utf-8') as s:
    a=[line.split() for line in s]
m=[]
with open('D:\python1\PAMPAM.txt','w',encoding='utf-8') as s:
    for i in a:
        for k in i[:len(i)-1]:
            print(k,file=s,end = ' ')
        b=float(i[len(i)-1])
        b = b - b*0.2
        print(b,file=s)
        print(' ')
        m.append(b)
n=str(max(m))
with open('D:\python1\PAMPAM.txt',encoding='utf-8') as s:
    a=[line.split() for line in s]
def f(x):
    for i in a:
        for k in i:
            if k == x:
                print('Информация о самом дорогом товаре,после уменьшения цены на 20%: ',*i)
f(n)