public String parseTernary(String expression) {
int len = expression.length();
for (int i = 0; i < len; i++) {
if (expression.charAt(i) == '?') {
else if (expression.charAt(i) == ':') {
// When the number of '?' matches with ':', we get a valid expression
if (expression.charAt(0) == 'T') {
// Get the expression before ':', skip 'T' and '?' at the beginning
return parseTernary(expression.substring(2, i));
// Get the expression after ':'
return parseTernary(expression.substring(i + 1));