public class CalcEngine {
  public static final int NULL = 0; //  (何もしない)
  public static final int ADD = 1; // 加算
  public static final int SUB = 2; // 減算
  public static final int MUL = 3; // 乗算
  public static final int DIV = 4; // 除算
  public static final int MOD = 5; // 剰余
  
  public static final int sqrt = 6;
  public static final int sin = 7;
  public static final int cos = 8;
  public static final int tan = 9;
  public static final int log = 10;
  public static final int exp = 11;

  static final int EMPTY   = 0;
  static final int ONE_NUM = 1;
  static final int ONE_OP  = 2;
  static final int TWO_NUM = 3;
  static final int ANSWER  = 4;
  static final int NEXT_NUM = 5;

  double regA, regB;
  int op;
  int state;
  
  CalcEngine() {
    regA = regB = 0.0;
    op = NULL;
    state = EMPTY;
  }
  
  public void reset() {
    regA = regB = 0.0;
    op = NULL;
  }


  public void register(double x) {
    switch (state) {
    case EMPTY:  regA = x; state = ONE_NUM;  break;
    case ONE_OP: regB = x; state = TWO_NUM;  break;
    case ANSWER: regA = x; state = NEXT_NUM; break;
    case ONE_NUM:  regA = x; break;
    case TWO_NUM:  regB = x; break;
    case NEXT_NUM: regA = x; break;
    default:
      System.err.println("内部エラー");
      System.exit(1);
    }
  }

  public double operate(int op) {
    if (state == TWO_NUM) {
      calculate();
    }
    this.op = op;
    state = ONE_OP;
    return regA;
  }

  public double getAnswer() {
    if (state == ONE_OP) {
      regB = regA;
    }
    calculate();
    state = ANSWER;
    return regA;
  }

  void calculate() {
    switch (this.op) {
    case ADD: regA = regA + regB; break;
    case SUB: regA = regA - regB; break;
    case MUL: regA = regA * regB; break;
    case DIV: regA = regA / regB; break;
    case MOD: regA = regA % regB; break;
    }
  }

 double function(int func) {
    if (state == TWO_NUM) {
      regB = funcall(func, regB);
      return regB;
    }
    else {
      regA = funcall(func, regA);
      return regA;
    }
  }

  double funcall(int func, double x) {
    switch (func) {
    case sqrt: return Math.sqrt(x);
    case sin: return Math.sin(radian(x));
    case cos: return Math.cos(radian(x));
    case tan: return Math.tan(radian(x));
    case log: return Math.log(x);
    case exp: return Math.exp(x);
    default: return x;
    }
  }

  public double radian(double deg) {
    return Math.PI * deg / 180.0;
  }

  // test program
  public static void main(String[] args) { // test program
    double ans = 0.0;
    CalcEngine ce = new CalcEngine();
    for (int i = 0; i < args.length; i++) {
      if (args[i].equals("="))
        ans = ce.getAnswer();
      else if (args[i].equals("+"))
        ans = ce.operate(ADD);
      else if (args[i].equals("-"))
        ans = ce.operate(SUB);
      else if (args[i].equals("*"))
        ans = ce.operate(MUL);
      else if (args[i].equals("/"))
        ans = ce.operate(DIV);
      
      else if (args[i].equals("%"))
        ans = ce.operate(MOD);
      
      else if (args[i].equals("sqrt"))
        ans = ce.operate(sqrt);
      else if (args[i].equals("sin"))
        ans = ce.operate(sin);
      else if (args[i].equals("cos"))
        ans = ce.operate(cos);
      else if (args[i].equals("tan"))
        ans = ce.operate(tan);
      
      else {
        try {
          ce.register(Double.parseDouble(args[i]));
        }
        catch (NumberFormatException e) {
          System.err.println(e);
        }
      }
    }
    System.out.println(ce.getAnswer());
  }
}