Dangling else grammar for Lex and Yacc

Question

I'm writing a small parser to recognize a subset of Java and I've run into an issue that I believe is called the dangling else problem.

My grammar for matching if-else statements started off like this:

statement:
block |
emptystatement |
ifstatement |
whilestatement |
statementexpression SEMICOLON |
OUTPUT LPAREN addexprlist RPAREN SEMICOLON
;

ifstatement:
IF LPAREN conditionalexpr RPAREN statement |
IF LPAREN conditionalexpr RPAREN statement ELSE statement

But I was receiving shift/reduce errors and wanted to fix those without just silencing them like most recommend.

I've modified my grammar to this one, which got rid of the shift/reduce errors, but now, it's not parsing the else statements correctly.

ifstatement:
matched |
unmatched
;

matched:
IF LPAREN conditionalexpr RPAREN matched ELSE matched 
;

unmatched: 
IF LPAREN conditionalexpr RPAREN matched |
IF LPAREN conditionalexpr RPAREN unmatched |
IF LPAREN conditionalexpr RPAREN matched ELSE unmatched |
/* empty */
;

I've been stuck on this for days now and can't wrap my head around how to fix it.

Here's an example of something it should parse:

if( n <= 0 )
       output(x);
 else {  //breaks on this else statement
   while( i < 0 ) {
       x = input();
       sum = sum + x;
       ++i;
   }