n = int(input "Nhap so:")
d = 0
x = 2

while d < n :
	flag = true
	for i in range (2,x)
		if x % i == 0
			flag = false
	if flag == true
		d = d + 1
		if d == n
			break
	x = x + 1
print ( "so nguyen to thu" + str(n) + "la" + str(x))