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######
import math
def abc():
    w = True
    a = float(input("请输入一个正整数："))
    if (a != abs(a)):
        print("错误")
    else:
        if(a % 1 != 0):
            print("错误")
        else:
            if ((int(a) == 1) or (int(a) == 0)):
                print("不是质数")
            else:   
                if(int(a) == 2):
                    print("是质数")
                else:
                    a = int(a)
                    q = 2
                    while(q < math.sqrt(a)):
                        if (a % q == 0):
                            print("不是质数")
                            w = False
                            break
                        else:
                            q += 1
                    if w :
                        print("是质数")
    if not((a == 1)or(a == 0)):
        t = 2
        print(a, '= ', end = '')
        while (t < (a + 1)):
            while (a % t == 0):
                if (a != t):
                    print(t, '× ', end = '')
                else:
                    print(a)
                    break
                a = int((a / t))
            t += 1
#####    
while True:
    abc()
#####