diff --git a/src/frontend/syntactic-analysis/bison-grammar.y b/src/frontend/syntactic-analysis/bison-grammar.y
index d36e898..372490d 100644
--- a/src/frontend/syntactic-analysis/bison-grammar.y
+++ b/src/frontend/syntactic-analysis/bison-grammar.y
@@ -61,6 +61,10 @@
 %token STRING
 
 // Reglas de asociatividad y precedencia (de menor a mayor):
+
+%precedence CLOSE_PARENTHESIS
+%precedence ELSE
+
 %left GREATER GREATER_EQUAL LESSER LESSER_EQUAL EQUAL NOT_EQUAL
 %left ADD SUB NOT
 %left MUL DIV AND OR
@@ -213,16 +217,16 @@ derivative: DERIVATIVE STRING IN OPEN_PARENTHESIS expression CLOSE_PARENTHESIS
     | derivative ERR positive_constant
     ;
 
-if_statement: IF OPEN_PARENTHESIS boolean CLOSE_PARENTHESIS OPEN_BRACKETS statements CLOSE_BRACKETS
-    | IF OPEN_PARENTHESIS boolean CLOSE_PARENTHESIS statement
+if_statement: IF OPEN_PARENTHESIS boolean CLOSE_PARENTHESIS statement
+    | IF OPEN_PARENTHESIS boolean CLOSE_PARENTHESIS OPEN_BRACKETS statements CLOSE_BRACKETS
     ;
 
-ifelse_statement: if_statement ELSE OPEN_BRACKETS statements CLOSE_BRACKETS
-    | ELSE statement
+ifelse_statement: if_statement ELSE statement
+    | if_statement ELSE OPEN_BRACKETS statements CLOSE_BRACKETS
     ;
 
-for_statement: FOR OPEN_PARENTHESIS declare_variable SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS OPEN_BRACKETS statements CLOSE_BRACKETS
-    | FOR OPEN_PARENTHESIS SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS OPEN_BRACKETS statements CLOSE_BRACKETS
+for_statement: FOR OPEN_PARENTHESIS declare_variable SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS OPEN_BRACES statements CLOSE_BRACES
+    | FOR OPEN_PARENTHESIS SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS OPEN_BRACES statements CLOSE_BRACES
     | FOR OPEN_PARENTHESIS declare_variable SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS statement
     | FOR OPEN_PARENTHESIS SEMICOLON boolean SEMICOLON assign_variable CLOSE_PARENTHESIS statement
     ;