#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

static int ch;

void error(char *s)
{
  fprintf(stderr, "%s\n", s);
  exit(EXIT_FAILURE);
}

void nextch()
{
  do {
    if ((ch = getchar()) == EOF) return;
  }while (ch == ' ' || ch == '\t');
}

double number()
{
  double x, a;
  int sign = '+';

  if (ch == '+' || ch == '-') {
    sign = ch; nextch();
  }
  if (! isdigit(ch)) error("Not a number or '(' is required.");
  x = ch - '0'; nextch();
  while (isdigit(ch)) {
    x = 10 * x + ch - '0';
    nextch();
  }
  if (ch == '.') {
    a = 1; nextch();
    while (isdigit(ch)) {
      x += (a /= 10) * (ch - '0');
      nextch();
    }
  }
  return sign == '-' ? -x : x;
}

double expression();

double factor()
{
  double x;

  if (ch != '(') return number();
  nextch(); x = expression();
  if (ch != ')') error("')' is required,");
  nextch(); return x;
}

double term() {
  double x, y;

  x = factor();
  while (1) {
    if (ch == '*') {
      nextch(); x *= factor();
    } else if (ch == '/') {
      nextch(); y = factor();
      if (y == 0) error("Zero division");
      x /= y;
    } else break;
  }
  return x;
}

double expression()
{
  double x;

  x = term();
  while (1) {
    if (ch == '+') {
      nextch(); x += term();
    } else if (ch == '-') {
      nextch(); x -= term();
    } else break;
  }
  return x;
}

int main()
{
  double x;

  nextch(); x = expression();
  if (ch != '\n') error("Syntax error");
  printf("%g\n", x);
  return EXIT_SUCCESS;
}