Please can anyone help, I have a problem to correctly connecting block9 to block 10 Also, block 19 to block 6.
\documentclass[border=3mm]{standalone}
% Required package
\usepackage{tikz}
\usetikzlibrary{shapes,positioning}
\usetikzlibrary{shapes,arrows}
\begin{document}
\begin{tikzpicture}[node distance = 0.3cm,auto][t]
\node[draw,
rounded rectangle,
minimum width=2.5cm,
minimum height=1cm] (block1) {START};
\node[draw,
below=of block1,
minimum width=3.5cm,
minimum height=0.75cm
] (block2) {block1};
\node[draw,
below=of block2,
minimum width=1.0cm,
minimum height=1cm
] (block3) {block2};
\node[draw,
diamond,
below=of block3,
minimum width=2.5cm,
inner sep=0] (block4) {block3};
\node[draw,
draw,
left=of block4,
minimum width=3.5cm,
minimum height=0.75cm
] (block5) {block4};
\node[draw,
draw,
below=of block4,
minimum width=3.5cm,
minimum height=0.75cm
] (block6) {block5};
\node[draw,
draw,
below=of block6,
minimum width=3.5cm,
minimum height=0.75cm
] (block7) {block6};
\node[draw,
diamond,
below=of block7,
minimum width=2.5cm,
inner sep=0] (block8) {block7};
\node[draw,
draw,
left=of block8,
minimum width=3.5cm,
minimum height=0.75cm
] (block9) {block8};
\node[draw,
draw,
below=of block8,
minimum width=3.5cm,
minimum height=0.75cm
] (block10) {block9};
\node[draw,
draw,
right=of block2,
minimum width=3.5cm,
minimum height=0.75cm
] (block11) {block10};
\node[draw,
draw,
below=of block11,
minimum width=3.5cm,
minimum height=0.75cm
] (block12) {block11};
\node[draw,
draw,
below=of block12,
minimum width=3.5cm,
minimum height=0.75cm
] (block13) {block12};
\node[draw,
draw,
below=of block13,
minimum width=3.5cm,
minimum height=0.75cm
] (block14) {block13};
\node[draw,
draw,
below=of block14,
minimum width=3.5cm,
minimum height=0.75cm
] (block15) {block14};
\node[draw,
draw,
below=of block15,
minimum width=3.5cm,
minimum height=0.75cm
] (block16) {block15};
\node[draw,
draw,
below=of block16,
minimum width=3.5cm,
minimum height=0.75cm
] (block17) {block16};
\node[draw,
draw,
below=of block17,
minimum width=3.5cm,
minimum height=0.75cm
] (block18) {block17};
\node[draw,
diamond,
below=of block18,
minimum width=2.5cm,
inner sep=0] (block19) {block18};
\node[draw,
draw,
left=of block19,
minimum width=3.5cm,
minimum height=0.75cm
] (block20) {block19};
\node[draw,
draw,
below=of block19,
minimum width=3.5cm,
minimum height=0.75cm
] (block21) {END};
% Arrows
\draw[-latex] (block1) edge (block2);
\draw[-latex] (block2) edge (block3);
\draw[-latex] (block3) edge (block4);
\draw[-latex] (block4) edge node[pos=0.3,inner sep=0pt]{Yes}(block6)
(block4) edge node[pos=0.15,inner sep=0pt]{No}(block5);
\draw[-latex] (block6) edge (block7);
\draw[-latex] (block7) edge (block8);
\draw[-latex] (block8) edge node[pos=0.3,inner sep=0pt]{Yes}(block9)
(block8) edge node[pos=0.25,inner sep=0pt]{No}(block10);
\draw[->] (block10) -| (block11);
\draw[-latex] (block11) edge (block12);
\draw[->] (block12) edge (block13);
\draw[->] (block13) edge (block14);
\draw[->] (block14) edge (block15);
\draw[->] (block15) edge (block16);
\draw[->] (block16) edge (block17);
\draw[->] (block17) edge (block18);
\draw[->] (block18) edge (block19);
\draw[-latex] (block19) edge node[pos=0.3,inner sep=0pt]{Yes}(block20)
(block19) edge node[pos=0.25,inner sep=0pt]{No}(block21);
\draw[->] (block20) |- (block7);
\end{tikzpicture}
\end{document}