func main()
	var s: []char :: cui@input()
	if(s =& null)
		do s :: ""
	end if
	do s :: @md5(@md5(s))
	do cui@print("\{s}\n")
end func

func md5(message: []char): []char
	var input: []bit8 :: #[^message]bit8
	for i(0, ^message - 1)
		do input[i] :: message[i] $ bit8
	end for
	ret @md5Sub(input)
end func

func md5Sub(message: []bit8): []char
	func leftRotate(x: bit32, c: int): bit32
		ret x.shl(c).or(x.shr(32 - c))
	end func
	
	var s: []int :: [
	|7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
	|5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20,
	|4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
	|6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21
	|]
	
	var k: []bit64 :: [
	|0xD76AA478b64, 0xE8C7B756b64, 0x242070DBb64, 0xC1BDCEEEb64,
	|0xF57C0FAFb64, 0x4787C62Ab64, 0xA8304613b64, 0xFD469501b64,
	|0x698098D8b64, 0x8B44F7AFb64, 0xFFFF5BB1b64, 0x895CD7BEb64,
	|0x6B901122b64, 0xFD987193b64, 0xA679438Eb64, 0x49B40821b64,
	|0xF61E2562b64, 0xC040B340b64, 0x265E5A51b64, 0xE9B6C7AAb64,
	|0xD62F105Db64, 0x02441453b64, 0xD8A1E681b64, 0xE7D3FBC8b64,
	|0x21E1CDE6b64, 0xC33707D6b64, 0xF4D50D87b64, 0x455A14EDb64,
	|0xA9E3E905b64, 0xFCEFA3F8b64, 0x676F02D9b64, 0x8D2A4C8Ab64,
	|0xFFFA3942b64, 0x8771F681b64, 0x6D9D6122b64, 0xFDE5380Cb64,
	|0xA4BEEA44b64, 0x4BDECFA9b64, 0xF6BB4B60b64, 0xBEBFBC70b64,
	|0x289B7EC6b64, 0xEAA127FAb64, 0xD4EF3085b64, 0x04881D05b64,
	|0xD9D4D039b64, 0xE6DB99E5b64, 0x1FA27CF8b64, 0xC4AC5665b64,
	|0xF4292244b64, 0x432AFF97b64, 0xAB9423A7b64, 0xFC93A039b64,
	|0x655B59C3b64, 0x8F0CCC92b64, 0xFFEFF47Db64, 0x85845DD1b64,
	|0x6FA87E4Fb64, 0xFE2CE6E0b64, 0xA3014314b64, 0x4E0811A1b64,
	|0xF7537E82b64, 0xBD3AF235b64, 0x2AD7D2BBb64, 0xEB86D391b64
	|]
	
	var a0: bit32 :: 0x67452301b32
	var b0: bit32 :: 0xEFCDAB89b32
	var c0: bit32 :: 0x98BADCFEb32
	var d0: bit32 :: 0x10325476b32
	
	var initialMessageLength: int :: ^message % (2 ^ 61) * 8
	do message :~ [0x80b8]
	var len: int :: ^message % (2 ^ 61)
	var padLen: int :: len < 56 ?(56 - len, 120 - len)
	do message :~ [0b8].repeat(padLen)
	for i(0, 7)
		do message :~ [(initialMessageLength % 256) $ bit8]
		do initialMessageLength :/ 256
	end for
	
	for ii(0, ^message / 64 - 1)
		var m: []bit32 :: #[16]bit32
		for i(0, 15)
			for j(3, 0, -1)
				do m[i] :* 256b32
				do m[i] :+ message[ii * 64 + 4 * i + j] $ bit32
			end for
		end for
		var a: bit32 :: a0
		var b: bit32 :: b0
		var c: bit32 :: c0
		var d: bit32 :: d0
		for i(0, 63)
			var f: bit32
			var g: int
			switch(i)
			case 0 to 15
				do f :: (b.and(c)).or(b.not().and(d))
				do g :: i
			case 16 to 31
				do f :: (d.and(b)).or(d.not().and(c))
				do g :: (5 * i + 1) % 16
			case 32 to 47
				do f :: b.xor(c).xor(d)
				do g :: (3 * i + 5) % 16
			case 48 to 63
				do f :: c.xor(b.or(d.not()))
				do g :: (7 * i) % 16
			end switch
			do f :+ a + k[i] $ bit32 + m[g]
			do a :: d
			do d :: c
			do c :: b
			do b :+ leftRotate(f, s[i])
		end for
		do a0 :+ a
		do b0 :+ b
		do c0 :+ c
		do d0 :+ d
	end for
	
	var md5: []bit8 :: #[16]bit8
	for i(0, 3)
		do md5[0 + i] :: a0.and(0xFFb32) $ bit8
		do md5[4 + i] :: b0.and(0xFFb32) $ bit8
		do md5[8 + i] :: c0.and(0xFFb32) $ bit8
		do md5[12 + i] :: d0.and(0xFFb32) $ bit8
		do a0 :: a0.shr(8)
		do b0 :: b0.shr(8)
		do c0 :: c0.shr(8)
		do d0 :: d0.shr(8)
	end for
	var res: []char :: #[32]char
	for i(0, 15)
		var val: []char :: md5[i] $ int.toStrFmt("02x")
		for j(0, 1)
			do res[2 * i + j] :: val[j]
		end for
	end for
	ret res
end func