import java.io.IOException; import java.io.InputStream; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.NoSuchElementException; class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private boolean hasNextByte() { if (ptr < buflen) { return true; }else{ ptr = 0; try { buflen = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;} public boolean hasNext() { skipUnprintable(); return hasNextByte();} public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while(isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } } public class Main { public static void main(String[] args) { long curtime=System.currentTimeMillis(); new Main().run(); System.err.println(System.currentTimeMillis()-curtime); } final long MOD=(long)1e9+7; long ans=0; ArrayList[] g; // int dfs(int cur,int par,int d) { // int sz=1; // for (int dst:g[cur]) { // if (dst==par) continue; // sz+=dfs(dst,cur,d+1); // } // ans+=d*sz%MOD; // if (ans>=MOD) ans-=MOD; // return sz; // } void run() { FastScanner sc=new FastScanner(); int N=(int)sc.nextLong(); g=new ArrayList[N]; for (int i=0;i(); boolean[] isroot=new boolean[N]; Arrays.fill(isroot, true); for (int i=0;i order=new ArrayList<>(); ArrayDeque stack=new ArrayDeque<>(); int[] d=new int[N]; int[] sz=new int[N]; stack.addFirst(root); while (!stack.isEmpty()) { int v=stack.pollFirst(); order.add(v); for (int dst:g[v]) { g[dst].remove((Integer)v); d[dst]=d[v]+1; stack.addFirst(dst); } } for (int i=order.size()-1;i>=0;--i) { int v=order.get(i); sz[v]=1; for (int dst:g[v]) sz[v]+=sz[dst]; ans+=(long)d[v]*sz[v]%MOD; if (ans>=MOD) ans-=MOD; } System.out.println(ans); } void tr(Object...objects) {System.out.println(Arrays.deepToString(objects));} }