//233

模板 LCA

void dfs(int x,int f){

    for(int i=0;i<E[x].size();i++){

        int v = E[x][i];

        if(v==f)continue;

        deep[v]=deep[x]+1;

        lca[v][0]=x;

        for(int j=1;j<maxm;j++){

            int fa = lca[v][j-1];

            if(fa==0)continue;

            lca[v][j]=lca[fa][j-1];

        }

        dfs(v,x);

    }

}

int up(int x,int d)

{

    for(int i=maxm-1;i>=0;i--)

    {

        if(d<(1<<i))continue;

        x=lca[x][i];

        d-=(1<<i);

    }

    return x;

}

int Lca(int x,int y)

{

    if(deep[x]>deep[y])swap(x,y);

    y=up(y,deep[y]-deep[x]);

    if(x==y)return x;

    for(int i=maxm-1;i>=0;i--)

    {

        if(lca[x][i]!=lca[y][i])

            x=lca[x][i],y=lca[y][i];

    }

    return lca[x][0];

}

//树链剖分

#include <cstdio>

#include <cstdlib>

#define maxm 200010

struct edge{int to,len,next;}E[maxm];

int cnt,last[maxm],fa[maxm],top[maxm],deep[maxm],siz[maxm],son[maxm],val[maxm];

void addedge(int a,int b,int len=0)

{

    E[++cnt]=(edge){b,len,last[a]},last[a]=cnt;

}

void dfs1(int x)

{

    deep[x]=deep[fa[x]]+1;siz[x]=1;

    for(int i=last[x];i;i=E[i].next)

    {

        int to=E[i].to;

        if(fa[x]!=to&&!fa[to]){

            val[to]=E[i].len;

            fa[to]=x;

            dfs1(to);

            siz[x]+=siz[to];

            if(siz[son[x]]<siz[to])son[x]=to;

        }

    }

}

void dfs2(int x)

{

    if(x==son[fa[x]])top[x]=top[fa[x]];

    else top[x]=x;

    for(int i=last[x];i;i=E[i].next)if(fa[E[i].to]==x)dfs2(E[i].to);

}

void init(int root){dfs1(root),dfs2(root);}

int query(int x,int y)

{

    for(;top[x]!=top[y];deep[top[x]]>deep[top[y]]?x=fa[top[x]]:y=fa[top[y]]);

    return deep[x]<deep[y]?x:y;

}

int n,m,x,y,v;

int main()

{

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

    for(int i=1;i<n;i++)

    {

        scanf("%d%d",&x,&y);addedge(x,y,v);addedge(y,x,v);

    }

    init(1);

    for(int i=1;i<=m;i++)

    {

        scanf("%d%d",&x,&y);

        printf("%d\n",query(x,y));

    }

    return 0 ;

}