1 var
2 ans,u,v,x,tot,kk,i,j,k,l,n,m,ee,s,t:longint;
3 d,last,next,long,other,e,head,num:array[0..200000]of longint;
4
5 function min(aa,bb:longint):longint;
6 begin
7 if aa>bb then exit(bb)
8 else exit(aa);
9 end;
10
11 procedure add(u,v,c:longint);
12 begin
13 inc(kk);
14 other[kk]:=kk+1;
15 e[kk]:=v;
16 next[kk]:=head[u];
17 head[u]:=kk;
18 long[kk]:=c;
19 inc(kk);
20 e[kk]:=u;
21 next[kk]:=head[v];
22 head[v]:=kk;
23 long[kk]:=0;
24 other[kk]:=kk-1;
25 end;
26
27 function dfs(x,flow:longint):longint;
28 var j,p:longint;
29 begin
30 if x=t then exit(flow);
31 dfs:=0; j:=last[x];
32 while j<>0 do
33 begin
34 if (long[j]>0)and(d[x]=d[e[j]]+1) then
35 begin
36 last[x]:=j;
37 p:=dfs(e[j],min(flow-dfs,long[j]));
38 dec(long[j],p); inc(long[other[j]],p);
39 dfs:=dfs+p;
40 if dfs=flow then exit;
41 end;
42 j:=next[j];
43 end;
44 if d[s]>tot then exit;
45 dec(num[d[x]]);
46 if num[d[x]]=0 then d[s]:=tot;
47 inc(d[x]);
48 last[x]:=head[x];
49 inc(num[d[x]]);
50 end;
51
52 begin
53 readln(n,m);
54 s:=0;t:=n+1;
55 for i:=1 to n do
56 begin
57 read(x);
58 if x=1 then
59 add(s,i,1)
60 else
61 add(i,t,1);
62 end;
63 for i:=1 to m do
64 begin
65 readln(u,v);
66 add(u,v,1);
67 add(v,u,1);
68 end;
69 tot:=t+1;
70 num[0]:=tot;
71 for i:=s to t do
72 last[i]:=head[i];
73 while d[s]<=tot do
74 ans:=ans+dfs(s,maxlongint);
75 writeln(ans);
76 end.
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