decode = function decode(input) {
	// Don't use UCS-2.
	var output = [];
	var inputLength = input.length;
	var i = 0;
	var n = initialN;
	var bias = initialBias;

	// Handle the basic code points: let `basic` be the number of input code
	// points before the last delimiter, or `0` if there is none, then copy
	// the first basic code points to the output.

	var basic = input.lastIndexOf(delimiter);
	if (basic < 0) {
		basic = 0;
	}

	for (var j = 0; j < basic; ++j) {
		// if it's not a basic code point
		if (input.charCodeAt(j) >= 0x80) {
			error('not-basic');
		}
		output.push(input.charCodeAt(j));
	}

	// Main decoding loop: start just after the last delimiter if any basic code
	// points were copied; start at the beginning otherwise.

	for (var index = basic > 0 ? basic + 1 : 0; index < inputLength;) /* no final expression */{

		// `index` is the index of the next character to be consumed.
		// Decode a generalized variable-length integer into `delta`,
		// which gets added to `i`. The overflow checking is easier
		// if we increase `i` as we go, then subtract off its starting
		// value at the end to obtain `delta`.
		var oldi = i;
		for (var w = 1, k = base;; /* no condition */k += base) {

			if (index >= inputLength) {
				error('invalid-input');
			}

			var digit = basicToDigit(input.charCodeAt(index++));

			if (digit >= base || digit > floor((maxInt - i) / w)) {
				error('overflow');
			}

			i += digit * w;
			var t = k <= bias ? tMin : k >= bias + tMax ? tMax : k - bias;

			if (digit < t) {
				break;
			}

			var baseMinusT = base - t;
			if (w > floor(maxInt / baseMinusT)) {
				error('overflow');
			}

			w *= baseMinusT;
		}

		var out = output.length + 1;
		bias = adapt(i - oldi, out, oldi == 0);

		// `i` was supposed to wrap around from `out` to `0`,
		// incrementing `n` each time, so we'll fix that now:
		if (floor(i / out) > maxInt - n) {
			error('overflow');
		}

		n += floor(i / out);
		i %= out;

		// Insert `n` at position `i` of the output.
		output.splice(i++, 0, n);
	}

	return String.fromCodePoint.apply(String, output);
}
Converts a Punycode string of ASCII-only symbols to a string of Unicode
symbols.
@memberOf punycode
@param {String} input The Punycode string of ASCII-only symbols.
@returns {String} The resulting string of Unicode symbols.