Повторно объявленный идентификатор

program censored;
var
 a:array[1..5,1..6] of real;
a[1,1] := 5.3; a[1,2] :=2.1; a[1,3] :=-3.2; a[1,4] :=-1.25; a[1,5] :=0.5; a[1,6]:=-3.05;
a[2,1] :=-0.25; a[2,2] :=7.1 ; a[2,3] :=4.3 ; a[2,4] := -0.7; a[2,5] :=-1.1 ;a[2,6]:=-0.15;
a[3,1] := 1.35; a[3,2] :=-2.5 ; a[3,3] := 6.83; a[3,4] := 0.35; a[3,5] :=1.8; a[3,6]:=-1.7;
a[4,1] := 2.25; a[4,2] :=0.9 ; a[4,3] :=-4.3 ; a[4,4] := 5.25; a[4,5] := -0.83; a[4,6]:=4.1;
a[5,1] :=-0.5 ; a[5,2] := -1.7; a[5,3] :=3.7 ; a[5,4] :=-1.25 ; a[5,5] :=8.9 ; a[5,6]:=2;
Procedure upor(a:real;n,m:integer);
var
i,j:integer;
p:boolean;
begin
for j:=1 to m do
p:=false;
while (not p) do
p:=true;
for i:1 to n-1 do
begin
if (m*(a[i+1,j]-a[i,j])<o)then
p=false;
c=a[i,j]
a[i,j]=a[i+1,j]
a[i+1,j]=c;
end;
begin
writeln('a=',a);
s=summ( a;1,5,1,6);
writeln ('s=',s);
end.

a[1,1] := 5.3; a[1,2] :=2.1; a[1,3] :=-3.2; a[1,4] :=-1.25; a[1,5] :=0.5; a[1,6]:=-3.05;
a[2,1] :=-0.25; a[2,2] :=7.1 ; a[2,3] :=4.3 ; a[2,4] := -0.7; a[2,5] :=-1.1 ;a[2,6]:=-0.15;
a[3,1] := 1.35; a[3,2] :=-2.5 ; a[3,3] := 6.83; a[3,4] := 0.35; a[3,5] :=1.8; a[3,6]:=-1.7;
a[4,1] := 2.25; a[4,2] :=0.9 ; a[4,3] :=-4.3 ; a[4,4] := 5.25; a[4,5] := -0.83; a[4,6]:=4.1;
a[5,1] :=-0.5 ; a[5,2] := -1.7; a[5,3] :=3.7 ; a[5,4] :=-1.25 ; a[5,5] :=8.9 ; a[5,6]:=2;