明明的随机数：
program ming;
var
i,j,n,m,x:integer;
a,b:array[1..100] of integer;
begin
readln(n);
m:=0;
for i:=1 to n do
read(a[i]);
for i:=1 to n do
for j:=i to n do
if a[i]>a[j] then
begin
x:=a[i]; a[i]:=a[j]; a[j]:=x;
end;
for i:=1 to n do
if a[i]<>a[i+1] then
b[i-m]:=a[i] else m:=m+1;
writeln(n-m);
for i:=1 to n-m do
begin
write(b[i]); write(' ');
end;
end.

校门外的树
program tree;
var aa:array[0..10000]of boolean;
m,n,i,j,a,b,s,l:integer;
aisdjkf:char;
begin
readln(l,m);
for a:=0 to l do
aa[a]:=true;
for a:=1 to m do
begin
readln(i,j);
for b:= i to j do aa[b]:=false;
end;
for a:=0 to l do if aa[a] then inc(s);
writeln(s);
end.