Count and Say

The count-and-say sequence is a list of strings of digits. Term 1 is "1". Each next term describes the previous one by reading its runs of equal digits aloud: how many, then which digit.

• Term 1: "1"
• Term 2: one 1, so "11"
• Term 3: two 1s, so "21"
• Term 4: one 2, one 1, so "1211"
• Term 5: one 1, one 2, two 1s, so "111221"

Return term n.

Examples

Example 1

Input:

count_and_say(4)

Output:

'1211'

Example 2

Input:

count_and_say(1)

Output:

'1'

Constraints

• 1 <= n <= 40
• Term 40 has about 63,000 digits.