print("Добропожаловатьвкалькулятор!Онумеетумножать,делить, складывать, вычитать, считать степень, синус, косинус, и вычислять tan ")
import cmd
import decimal
import sys
import math
from math import sin, tan, cos, sqrt
from decimal import *
c = True
while c == True:
    k = input()
    l = k.rstrip('1,2,3,4,5,6,7,8,9,0, ')
    a = l.rstrip('+, ,sqrt,sin,cos,tan,*,/,**,-')
    j = k.lstrip('1,2,3,4,5,6,7,8,9,0, ')
    b = j.lstrip(' ,+,-,*,/,**,sin,cos,sqrt,tan')
    s = k.strip('1,2,3,4,5,6,7,8,9,0, ')
    a = float(a)

    if b == None:
        b = 0
    elif b != None:
        b = float(b)
    if s in('+','-','*','/','**','sqrt','sin','tan'):
        if s == '+':
            summa = a + b
            print(a, '+', b, '=', summa)
        elif s== '-':
            summa = a - b
            print (a, '-', b, '=', summa)
        elif s =='*':
            summa = a * b
            print(a, '*',b, '=', summa)
        elif s == '/':
            summa = a / b
            print(a, '/',b , '=', summa)
        elif s == '**':
            summa = a ** b
            print(a, '**', b, '=', summa)
        elif s == 'sqrt':
            summa = a
            print(math.sqrt(summa))
        elif s == 'sin':
            summa = a
            print(sin(summa))
        elif s == 'tan':
            summa = a
            print(tan(summa))
        while summa != None:
            a = summa
            k = input()
            if k != 0:

                b = k.lstrip('+,-,*,/,**,sqrt,sin,cos,tan,end, ')
                s = k.strip('1,2,3,4,5,6,7,8,9,0, ')

            elif k == None:
                    b = 0
            if s in ('+','-','*','/', '**', 'sqrt', 'sin', 'tan','c'):
                if s =='+':
                    b = float(b)
                    summa = a + b
                    print(a, '+', b, '=', summa)
                elif s== '-':
                    b = float(b)
                    summa = a - b
                    print (a, '-', b, '=', summa)
                elif s =='*':
                    b = float(b)
                    summa = a * b
                    print(a, '*',b, '=', summa)
                elif s == '/':
                    b = float(b)
                    summa = a / b
                    print(a, '/',b , '=', summa)

                elif s == '**':
                    b = float(b)
                    summa = a ** b
                    print(a, '**', b, '=', summa)
                elif s == 'sqrt':
                    b = float(b)
                    print(math.sqrt(a))
                elif s == 'sin':
                    b = float(b)
                    print(sin(a))
                elif s == 'tan':
                    b = float(b)
                    print(tan(a))
                elif s == 'c':
                    c == True