G = ({program, statement_list, statement, assignment_stmt, input_stmt, output_stmt, if_stmt, for_stmt, array_decl_stmt, condition, increment_stmt, expression, term, factor, relational_operator, binary_operator, concatenation},{=, (, ), [, ], if, else, for, ARRAY, echo, readline, +, -, *, /, <, <=, ==, >=, !=, ++, --, :, ;, IDENTIFIER, INTEGER_CONST, FLOAT_CONST, STRING_CONST},P, program)

P :
    program -> statement_list

    statement_list -> statement | statement statement_list

    statement -> assignment_stmt | input_stmt | output_stmt | if_stmt | for_stmt | array_decl_stmt

    assignment_stmt -> IDENTIFIER = expression

    input_stmt -> IDENTIFIER = readline_function ( STRING_CONST )

    output_stmt -> echo_function ( STRING_CONST concatenation IDENTIFIER )

    if_stmt -> if ( condition ) : statement | if ( condition ) : statement else : statement

    for_stmt -> for ( assignment_stmt ; condition ; increment_stmt ) : statement

    array_decl_stmt -> IDENTIFIER = ARRAY [ INTEGER_CONST ]

    condition -> expression relational_operator expression

    increment_stmt -> IDENTIFIER ++ | IDENTIFIER --

    expression -> term | term binary_operator expression

    term -> factor | factor binary_operator term

    factor -> IDENTIFIER | INTEGER_CONST | FLOAT_CONST | STRING_CONST

    relational_operator -> < | <= | == | >= | !=

    binary_operator -> + | - | * | /

    concatenation -> +

    echo_function -> echo

    readline_function -> readline