def isprime(n):
    n = abs(int(n))
    if n < 2:
        return False
    if n == 2: 
        return True    
    if not n & 1: 
        return False
    for x in range(3, int(n**0.5)+1, 2):
        if n % x == 0:
            return False
    return True

def primecount(n):
    cnt=0
    for i in range(1,n+1):
        if isprime(i):
            cnt+=1
    print cnt 
    
def nthprime(n):
    cnt=1
    i=1
    while cnt!=n:
        if isprime(i):
            cnt+=1
        i+=1
    print i-1  
while 1:
        try:
                
                    ch=int(raw_input('\n1.the prime-counting function\n2.nth-prime function \n3. Exit'))
                    
                    if ch==1:
                           n=int(raw_input('Enter a Number '))
                           primecount(n)
                    elif ch==2:
                            n=int(raw_input('Enter a Number'))
                            nthprime(n)
                    elif ch==3:
                            print 'Bye Bye'
                            exit()
                    else:
                            print 'Wrong Input'
        except:
            print 'Exception!!!'
            exit()
                   
                        

1.the prime-counting function
2.nth-prime function 
3. ExitException!!!