第二个点是一个环，度为奇数的点为0个，但是好要一笔花完，这里就加一个特判，
by ljc20020730 @ 2017-01-26 14:39:03
```cpp
var n,m,x,y,ans,i:longint;
d:array[1..1000]of longint;
begin
readln(n,m);
if m=0 then begin writeln(0); halt; end;
for i:=1 to m do begin
readln(x,y);
inc(d[x]);
inc(d[y]);
end;
for i:=1 to n do
if d[i] mod 2=1 then inc(ans);
if ans=0 then write(1)else writeln(ans div 2);
end.
```
by ljc20020730 @ 2017-03-10 20:35:41