program matrix;
uses crt;
const nn=20 ;mm=20;
type mas=array[1..nn,1..mm] of real;
var x:mas; a:real;n,m,i,j:byte;
begin
 clrscr;
repeat
write('Enter N');
readln(n);
write('Enter M');
readln(m);
until (n>0)and(n<=20)and(m>0)and(m<=20);
writeln('N= ',n,' M= ', m);
for i:=1 to n  do
for j:=1 to m    do
begin
write('x[',i,',',j,']=');
readln(x[i,j]);
     end;


writeln(' ');
for i:=1 to n do begin
for j:=1 to m do
write(x[i,j]:8:2);
writeln;      end;
a:=0;
For i:=1 to n     do begin
for j:=1 to m       do  begin
if x[i,j]/3=trunc(x[i,j]/3) then a:=a+x[i,j]; end;  end;
writeln('a=',a:8:2);
readln
end.