Даны три матрицы А(3,5), В(6,4), С(7,2). Если сумма всех элементов матрицы больше 0, то у первого элемента этой матрицы заменит знак на противоположный — Pascal(Паскаль)

uses crt;
var a,b,c:array[1..20,1..20] of integer;
    i,j,sum1,sum2,sum3:integer;
begin
ClrScr;
Randomize;
for i:=1 to 3 do
 begin
  for j:=1 to 5 do
   begin
    a[i,j]:=random(20)-10;
    Write(a[i,j]:4);
   end;
  Writeln;
 end;
Writeln;
for i:=1 to 6 do
 begin
  for j:=1 to 4 do
   begin
    b[i,j]:=random(20)-10;
    Write(b[i,j]:4);
   end;
  Writeln;
 end;
Writeln;
for i:=1 to 7 do
 begin
  for j:=1 to 2 do
   begin
    c[i,j]:=random(20)-10;
    Write(c[i,j]:4);
   end;
  Writeln;
 end;
sum1:=0;
sum2:=0;
sum3:=0;
  for i:=1 to 3 do
   for j:=1 to 5 do
    sum1:=sum1+a[i,j];
  for i:=1 to 6 do
   for j:=1 to 4 do
    sum2:=sum2+b[i,j];
  for i:=1 to 7 do
   for j:=1 to 2 do
    sum3:=sum3+c[i,j];
 if sum1<0 then
  a[1,1]:=-a[1,1];
 if sum1<0 then
  b[1,1]:=-b[1,1];
 if sum1<0 then
  c[1,1]:=-c[1,1];
Readln;
Writeln('Sum1 ',sum1);
Writeln('Sum2 ',sum2);
Writeln('Sum3 ',sum3);
Readln;
Writeln;
for i:=1 to 3 do
 begin
  for j:=1 to 5 do
   begin
    a[i,j]:=random(20)-10;
    Write(a[i,j]:4);
   end;
  Writeln;
 end;
Writeln;
for i:=1 to 6 do
 begin
  for j:=1 to 4 do
   begin
    b[i,j]:=random(20)-10;
    Write(b[i,j]:4);
   end;
  Writeln;
 end;
Writeln;
for i:=1 to 7 do
 begin
  for j:=1 to 2 do
   begin
    c[i,j]:=random(20)-10;
    Write(c[i,j]:4);
   end;
  Writeln;
 end;
Readln;
end.