太离谱了！ usaco考试过了 来这tle?

#include<cstdio>
#include<iostream>
#include<cmath>
using namespace std;
const int N=100009;
int ans=0;
struct E
{
    int p;
    int to;
    int nex;
}Edge[N*2];
int now=0;
int head[N],depth[N];
bool vis[N];
void add(int x,int y,int z)
{
    Edge[++now].to=y;
    Edge[now].nex=head[x];
    head[x]=now;
    Edge[now].p=z;
}
int dfs(int x,int parent)
{
    int coun=0;
    depth[x]=parent;
    vis[x]=true;
    for(int i=head[x];i;i=Edge[i].nex)
    {
        if(!vis[Edge[i].to])
        {
            coun++;
            dfs(Edge[i].to,x);
            ans++;
        }
    }
    coun++;
    ans+=ceil(log(coun)/log(2));
}

int main()
{
    int n;
    int a,b;
    cin>>n;
    for(int i=1;i<=n-1;i++)
    {
        cin>>a>>b;
        add(a,b,1);
        add(b,a,1);
    }
    dfs(1,0);
    cout<<ans;
}