program polska;

const SIZE = 10;
type
    stack = array[0..SIZE] of integer;
    opstack = array[0..SIZE] of char;
var i, j, len, n, nStackPointer, opStackPointer:integer;
    numberStack: stack;
    operatorStack: opstack;
    source : string;

//==============================================================================
function evalExpression(var nStack, oStack: integer) : integer; forward;


procedure fillStack;
var i, temp: integer;
begin
  nStackPointer := 0;
  opStackPointer := 0;
  for i := len downto 1 do
    case source[i] of
    '+','-','*','/':
        begin
          operatorStack[opStackPointer] := source[i];
          Inc(opStackPointer);
          Temp := evalExpression(nStackPointer, opStackPointer);
          numberStack[nStackPointer] := Temp;
            Inc(nStackPointer);
        end;
      '0'..'9':
        begin
          numberStack[nStackPointer] := Ord(source[i]) - Ord('0');
          Inc(nStackPointer);
        end;
      end;
end;

//==============================================================================

function evalExpression(var nStack, oStack : integer) : integer;
    var result, i, j: integer;
        tmp : char;
    begin
      i := numberStack[nStack - 1];
      j := numberStack[nStack - 2];
      tmp := operatorStack[oStack - 1];
      Dec(nStack, 2);
        Dec(oStack);
      case tmp of
        '*': result := i * j;
        '+': result := i + j;
        '-': result := i - j;
        '/': result := i div j;
      end;
    evalExpression := result;
    end;
//===============================================================================
begin
  ReadLn(source);
  len := Length(source);
  fillStack;
  writeln(numberStack[0]);
end.