\documentclass{article}
\usepackage{amsmath,amssymb} 
\usepackage{pstricks}
\usepackage{pst-node}
\usepackage{pst-blur}
\definecolor{Blue}{rgb}{1.,0.75,0.8}

% ================================
% Source: http://tug.org/pipermail/pstricks/2009/006766.html

\makeatletter
\newdimen\psparallelogramsep
\def\psset@parallelogramsep#1{\pssetlength\psparallelogramsep{#1}}
\psset@parallelogramsep{3mm}
\def\psparallelogrambox{\pst@object{psparallelogrambox}}
\def\psparallelogrambox@i{\pst@makebox\psparallelogrambox@ii}
\def\psparallelogrambox@ii{%
    \begingroup
    \pst@useboxpar
    \pst@dima=\pslinewidth
    \advance\pst@dima by \psframesep
    \pst@dimc=\wd\pst@hbox\advance\pst@dimc by \pst@dima
    \pst@dimb=\dp\pst@hbox\advance\pst@dimb by \pst@dima
    \pst@dimd=\ht\pst@hbox\advance\pst@dimd by \pst@dima
    \setbox\pst@hbox=\hbox{%
        \ifpsboxsep\kern\pst@dima\fi
        \begin@ClosedObj
        \addto@pscode{%
            \psk@cornersize
            \pst@number\pst@dima neg
            \pst@number\pst@dimb neg
            \pst@number\pst@dimc
            \pst@number\pst@dimd .5
            \pst@number\psparallelogramsep
            \tx@Parallelogram}%
            \def\pst@linetype{2}%
            \showpointsfalse
        \end@ClosedObj
        \box\pst@hbox
        \ifpsboxsep\kern\pst@dima\fi%
    }%
    \ifpsboxsep\dp\pst@hbox=\pst@dimb\ht\pst@hbox=\pst@dimd\fi
    \leavevmode\box\pst@hbox
    \endgroup%
}

% From the Frame and Rect PostScript macros
\pst@def{Parallelogram}<{%
/ParallelogramA {
x1 pgs sub y1 moveto
x1 y2 lineto
x2 pgs add y2 lineto
x2 y1 lineto
x1 pgs sub y1 lineto
closepath} def
%
/pgs ED
CLW mul
/a ED
3 -1 roll
2 copy gt { exch } if
a sub
/y2 ED
a add
/y1 ED
2 copy gt { exch } if
a sub
/x2 ED
a add
/x1 ED
1 index 0 eq {pop pop ParallelogramA } { OvalFrame } ifelse}>
\makeatother

\def\pspbox[#1]#2{\makebox[#1]{\psparallelogrambox{#2}}}

% ================================
\pagestyle{empty}

\begin{document}

\vspace{0.5cm}
\small
  \psset{shadowcolor=black!70,shadowangle=-90,blur=true}
  \begin{psmatrix}[rowsep=0.5,colsep=0.3]% defines the distance between two frames 
   %Begin
    \psovalbox[fillstyle=solid, fillcolor=yellow!30]{Start} \\
   %Input 
    \psparallelogrambox[fillstyle=solid,fillcolor=blue!20]{Input m and d} \\
    %Condition
    \psdiabox[fillstyle=solid, fillcolor=magenta!20]{$m \leqslant 6 $} &
       %computation
       \psframebox[shadow=true]{$(m-1)*31 +d \implies a$}  \\
    \psframebox{$(6*31)+30(m-1) +d \implies a$} \\
     %Output
      \psparallelogrambox[fillstyle=solid,fillcolor=blue!20]{Print a} \\
  %End
    \psovalbox[fillstyle=solid, fillcolor=yellow!30]{End}
    % Links
    \ncline{->}{1,1}{2,1}
    \ncline{->}{2,1}{3,1}
    \ncline{->}{3,1}{4,1}<{\textcolor{red}{No}}
    \ncline{->}{4,1}{5,1}
    \ncline{->}{5,1}{6,1}
    \ncline{->}{3,1}{3,2}^{\textcolor{red}{Yes}}
    \ncbar[angleA=-90,armB=0,nodesepB=0.25]{->}{3,2}{4,1}
  \end{psmatrix} 
\end{document}