@onlyicelover 应该，是可以的吧。
使暴风雨沉静下来的是纤弱的大波斯菊，愿艾德布洛伊的祝福伴随着你。
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Program p1091;
var i,j,k,l,m,n,p,ans:longint;
a1,a2,a3:array[-2..300,-1..300]of longint;
pt:array[1..300,1..2]of longint;
fl:array[1..300]of boolean;
procedure sy(z:longint); var x,y:longint;
begin
for x:=1 to p do begin
if (pt[x,1]=z)and(fl[pt[x,2]]=false)then
begin inc(a1[z,0]);a1[a1[z,0]]:=pt[x,2];a1[pt[x,2],-2]:=a1[z,-2]+1;
fl(pt[x,2]):=true;sy(pt[x,2]);a1[pt[x,2],-1]:=z;
end;
if (pt[x,2]=z)and(fl[pt[x,1]]=false)then
begin inc(a1[z,0]);a1[a1[z,0]]:=pt[x,1];a1[pt[x,1],-2]:=a1[z,-2]+1;
fl(pt[x,1]):=true;sy(pt[x,1]);a1[pt[x,1],-1]:=z;
end;
end;
end;
Procedure dfs(x:longint);
begin
end;
begin
read(n,p);
for i:=1 to p do
read(pt[i,1],pt[i,2]);
for i:=1 to 300 do fl[i]:=false;
fl[1]:=true;
for i:=1 to n do begin a1[i,0]:=0;end;a1[1,-2]:=1;
sy(1);