Here is my program:

program conference;
const max=1000;
var map:array[1..max,1..max] of boolean;
    link:array[1..max] of longint;
    cover:array[1..max] of boolean;
    n,m,k:longint;
procedure readdata;
var i,j,a,b:longint;
begin
readln(n,m,k);
for i:=1 to k do
 begin
  readln(a,b);
  map[a][b]:=true;
 end;
end;
function find(i:longint):boolean;
var k,p:longint;
begin
find:=true;
for k:=1 to m do
 if map[i][k] and not cover[k] then
  begin
   p:=link[k];link[k]:=i;cover[k]:=true;
   if (p=0) or find(p) then exit;
   link[k]:=p;
  end;
find:=false;
end;
procedure main;
var x:longint;
begin
for x:=1 to n do
 begin
  fillchar(cover,sizeof(cover),0);
  find(x);
 end;
end;
procedure print;
var i,j,step:longint;
begin
step:=0;
for i:=1 to m do
 if link[i]<>0 then inc(step);
writeln(n+m-step);
end;
BEGIN
readdata;
main;
print;
END.