1 //  2 //by coolxxx  3 //#include<bits/stdc++.h>  4 #include<iostream>  5 #include<algorithm>  6 #include<string>  7 #include<iomanip>  8 #include<map>  9 #include<stack> 10 #include<queue> 11 #include<set> 12 #include<bitset> 13 #include<memory.h> 14 #include<time.h> 15 #include<stdio.h> 16 #include<stdlib.h> 17 #include<string.h> 18 //#include<stdbool.h> 19 #include<math.h> 20 #define min(a,b) ((a)<(b)?(a):(b)) 21 #define max(a,b) ((a)>(b)?(a):(b)) 22 #define abs(a) ((a)>0?(a):(-(a))) 23 #define lowbit(a) (a&(-a)) 24 #define sqr(a) ((a)*(a)) 25 #define swap(a,b) ((a)^=(b),(b)^=(a),(a)^=(b)) 26 #define mem(a,b) memset(a,b,sizeof(a)) 27 #define eps (1e-8) 28 #define J 10 29 #define mod 1000000007 30 #define MAX 0x7f7f7f7f 31 #define PI 3.14159265358979323 32 #define N 1004 33 using namespace std; 34 typedef long long LL; 35 int cas,cass; 36 int n,m,lll,ans; 37 int fa[N],pre[N],num[N],e[N],t[N],last[N],in[N],q[N]; 38 bool f[N][N]; 39 bool u[N]; 40 struct xxx 41 { 42     int next,to; 43 }a[N]; 44 void cover(int x) 45 { 46     int i=e[x]; 47     fa[x]=x; 48     num[x]=1; 49     while(i!=x) 50     { 51         num[x]++; 52         num[i]=0; 53         fa[i]=x; 54         i=e[i]; 55     } 56 } 57 void dfs(int u) 58 { 59     if(t[u]) 60     { 61         if(t[u]>cass)cover(u); 62         return; 63     } 64     t[u]=++cas; 65     //fa[u]=e[u]; 66     dfs(e[u]); 67 } 68 void add(int x,int y) 69 { 70     a[++lll].next=last[x]; 71     a[lll].to=y; 72     last[x]=lll; 73 } 74 int work(int now) 75 { 76     int i,to,sum=0; 77     for(i=last[now];i;i=a[i].next) 78     { 79         to=a[i].to; 80         sum+=work(to); 81     } 82     return sum+num[now]; 83 } 84 void spfa() 85 { 86     int i,l=0,r=0,now,to; 87     mem(u,0);cas=0; 88     for(i=1;i<=n;i++) 89         if(!in[i] && num[i])q[++cas]=i,pre[i]=work(i); 90 } 91  92 int main() 93 { 94     #ifndef ONLINE_JUDGE 95 //    freopen("1.txt","r",stdin); 96 //    freopen("2.txt","w",stdout); 97     #endif 98     int i,j,k; 99     int x,y,z;100 //    for(scanf("%d",&cass);cass;cass--)101 //    for(scanf("%d",&cas),cass=1;cass<=cas;cass++)102 //    while(~scanf("%s",s+1))103     while(~scanf("%d",&n))104     {105         lll=0;mem(num,0);mem(t,0);mem(in,0);mem(last,0);mem(pre,0);mem(f,0);106         scanf("%d",&m);107         for(i=1;i<=n;i++)108         {109             scanf("%d",&e[i]);110             num[i]=1;fa[i]=i;111         }112         cas=0;113         for(i=1;i<=n;i++)114         {115             if(t[i])continue;116             cass=cas;117             dfs(i);118         }119         for(i=1;i<=n;i++)120         {121             if(num[i]==0 || fa[e[i]]==i)continue;122             add(fa[e[i]],i);123             in[i]++;124         }125         spfa();126         f[0][0]=1;127         for(i=1;i<=cas;i++)128         {129             x=q[i];y=q[i-1];130             for(j=0;j<=m;j++)131             {132                 f[x][j]|=f[y][j];133                 for(k=num[x];k<=pre[x] && j+k<=m;k++)134                     f[x][j+k]|=f[y][j];135             }136         }137         x=q[cas];138         for(i=m;i;i--)139             if(f[x][i])break;140         printf("%d\n",i);141     }142     return 0;143 }144 /*145 //146 147 //148 */