public static void main ( String [ ] args ) throws IOException {
  BufferedReader r = new BufferedReader ( new InputStreamReader ( System . in ) , 1 ) ;
  String s = r . readLine ( ) ;
  int n = s . length ( ) ;
  int [ ] [ ] a = {
    {
      0 , - 1 }, {
        1 , 0 }
      };
      int p = 0 ;
      for ( int i = 0 ;
      i < n ;
      i ++ ) {
        p += a [ i % 2 ] [ s . charAt ( i ) == 'g' ? 0 : 1 ] ;
      }
      System . out . println ( p ) ;
    }
    
public static void main ( String [ ] args ) throws IOException { BufferedReader r = new BufferedReader ( new InputStreamReader ( System . in ) , 1 ) ; String s = r . readLine ( ) ; int n = s . length ( ) ; int [ ] [ ] a = { { 0 , - 1 } , { 1 , 0 } } ; int p = 0 ; for ( int i = 0 ; i < n ; i ++ ) { p += a [ i % 2 ] [ s . charAt ( i ) == ' g ' ? 0 : 1 ] ; } System . out . println ( p ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_identifier)) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))) (decimal_integer_literal))))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_initializer (array_initializer (decimal_integer_literal) (unary_expression operand: (decimal_integer_literal))) (array_initializer (decimal_integer_literal) (decimal_integer_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (array_access array: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) index: (ternary_expression condition: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal)) consequence: (decimal_integer_literal) alternative: (decimal_integer_literal))))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))