#include<cstdio>

#include<vector>

#include<cstring>

using namespace std;

const int maxn=;

vector<int> G[maxn];

const int INF=0x3f3f3f3f;

int dp[][maxn];

int f[maxn][maxn];

int res[maxn][maxn];

void dfs(int u,int fa)

{

    if (G[u].size()==)

    {

        f[u][]=f[u][]=;

        if (fa==-) res[u][]=res[u][]=;

        else res[u][]=res[u][]=;

    }

    else

    {

        for (int i=;i<G[u].size();i++)

        {

            int v=G[u][i];

            dfs(v,u);

        }

        memset(dp,INF,sizeof(dp));

        dp[][]=;

        for (int i=;i<=G[u].size();i++)

        {

            for (int j=;j<=;j++)

            {

                dp[i&][j]=INF;

                for (int k=;k<=j;k++)

                {

                    dp[i&][j]=min(dp[i&][j],dp[i&^][j-k]+f[G[u][i-]][k]+(k==));

                }

            }

        }

        f[u][]=;

        if (fa==-) res[u][]=;

        else res[u][]=;

        for (int i=;i<=;i++) f[u][i]=dp[G[u].size()&][i-];

        for (int i=;i<=;i++) res[u][i]=f[u][i]+(fa!=-);

    }

}

int main()

{

    memset(f,INF,sizeof(f));

    memset(res,INF,sizeof(res));

    int n,P;

    scanf("%d%d",&n,&P);

    for (int i=;i<n;i++)

    {

        int u,v;

        scanf("%d%d",&u,&v);

        G[u].push_back(v);

    }

    dfs(,-);

    int ans=INF;

    for (int i=;i<=n;i++) ans=min(ans,res[i][P]);

    printf("%d\n",ans);

    return ;

}