Bison - Shift/reduce conflicts

Question

I am getting 3 shift/reduce conflicts after I wrote the expression grammars. The math operation expressions were fine but when I wrote the 'TOKEN_MINUS expression %prec UMINUS' statement, there were 3 shift.reduce conflicts. I'm not sure how to fix this. Please help me.

%{
#define YYDEBUG 1
#include <stdio.h>
int yylex();
extern int yylineno;
extern int yyerror (const char *);
%}

%debug
%locations
%define parse.error detailed

%token TOKEN_NUMBER
%token TOKEN_THEN
%token TOKEN_END
%token TOKEN_STOP
%token TOKEN_DO
%token TOKEN_IDENT
%token TOKEN_READ
%token TOKEN_world
%token TOKEN_NEWLINE
%token TOKEN_IF
%token TOKEN_ELSEIF
%token TOKEN_WHILE
%token TOKEN_POWER TOKEN_MULTIPLY
%token TOKEN_PROGRAM
%token TOKEN_ELSE
%token TOKEN_MINUS
%token TOKEN_WRITE
%token TOKEN_ENDIF
%token TOKEN_ENDWHILE
%token TOKEN_FULL_STOP
%token TOKEN_EXCLAMATION_POINT
%token TOKEN_COMMA
%token TOKEN_LEFT_PARENTHESIS
%token TOKEN_RIGHT_PARENTHESIS
%token TOKEN_COLON
%token TOKEN_ASSIGNMENT TOKEN_DOUBLE_ASSIGNMENT
%token TOKEN_DIV
%token TOKEN_GREATER_THAN
%token TOKEN_LESS_THAN
%token TOKEN_STRING
%token TOKEN_STRINGS
%token TOKEN_ADD
%token TOKEN_REAL
%token TOKEN_GT
%left TOKEN_ADD
%left TOKEN_MINUS
%left TOKEN_MULTIPLY 
%left TOKEN_DIV
%right UMINUS
%right TOKEN_POWER

%%

program:
    statements
    ;

statements:
    statements statement
    | statement
    ; 

statement: 
    simple_stmts
    ;

simple_stmts:
    simple_stmt TOKEN_NEWLINE
    | simple_stmt
    ;

simple_stmt:
    expression
    | write_stmt
    | read_stmt
    | assignment
    ;

write_stmt:
    TOKEN_WRITE atom
    ;

read_stmt:
    TOKEN_READ expression
    ;

assignment:
    TOKEN_IDENT TOKEN_ASSIGNMENT expression
    ;

expression:
    expression TOKEN_ADD expression
    | expression TOKEN_MINUS expression
    | expression TOKEN_MULTIPLY expression
    | expression TOKEN_DIV expression
    | expression TOKEN_POWER expression
    | TOKEN_MINUS expression %prec UMINUS
    | atom TOKEN_COMMA
    | atom
    ;

atom:
    TOKEN_IDENT
    | TOKEN_STRINGS
    | TOKEN_PROGRAM
    | TOKEN_STOP
    | TOKEN_REAL
    | TOKEN_END
    | TOKEN_NUMBER
    | TOKEN_LEFT_PARENTHESIS expression TOKEN_RIGHT_PARENTHESIS
    ;



%%

int yyerror( const char *s ) {
    fprintf(stderr, "Error at line %d: %s\n", yylineno, s);
    return 1;
}

When I delete the 'TOKEN_MINUS expression %prec UMINUS' from the code, the conflicts go away but I believe I need this statement.