#Python代码
from random import *
from time import *
fuhao = input('1-加法,2-乘法,否则退出')
n = int(input('位数>>>'))
m = int(input('题目数量(输入0则无限)>>>'))
t1,count = time(),0
if fuhao == '1':
    if m == 0:
        while True:
            a,b = randint(10**(n-1),10**n-1),randint(10**(n-1),10**n-1)
            try:
                ans = int(input('%d+%d=' %(a,b)))
                if a+b == ans:
                    count += 1
                    t2 = time()-t1
                else:
                    print('错误,正确答案是',a+b)
                    break
            except:
                print('输入错误,跳过')
    else:
        for i in range(m):
            a,b = randint(10**(n-1),10**n-1),randint(10**(n-1),10**n-1)
            try:
                ans = int(input('%d+%d=' %(a,b)))
                if a+b == ans:
                    count += 1
                else:
                    print('错误,正确答案是',a+b)
            except:
                print('输入错误,跳过')
        t2 = time()-t1
elif fuhao == '2':
    if m == 0:
        while True:
            try:
                a,b = randint(10**(n-1),10**n-1),randint(10**(n-1),10**n-1)
                ans = int(input('%d*%d=' %(a,b)))
                if a*b == ans:
                    count += 1
                    t2 = time()-t1
                else:
                    print('错误,正确答案是',a*b)
                    break
            except:
                print('输入错误,跳过')
    else:
        for i in range(m):
            try:
                a,b = randint(10**(n-1),10**n-1),randint(10**(n-1),10**n-1)
                ans = int(input('%d*%d=' %(a,b)))
                if a*b == ans:
                    count += 1
                else:
                    print('错误,正确答案是',a*b)
            except:
                print('输入错误,跳过')
        t2 = time()-t1
else:
    quit()
print('你答对了%d道题,用时%.2f秒' % (count,t2))