谁有去年NOIP采药程序？（要全对的）

program p1104;
var t:integer;
m:integer;
w:array[0..1000] of integer;

i,j:integer;
a,b:integer;

begin
readln(t,m);
fillchar(w,sizeof(w),0);
for i:=1 to m do begin
readln(a,b);
for j:=t-a downto 0 do begin
if (w[j]+b)>w[j+a] then w[j+a]:=w[j]+b;
end;
end;
writeln(w[t]);
end.