import std.conv, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(T)(in T[] as, in bool delegate(T) test) { int low = -1, upp = cast(int)(as.length); for (; low + 1 < upp; ) { int mid = (low + upp) >> 1; (test(as[mid]) ? low : upp) = mid; } return upp; }
int lowerBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a < val)); }
int upperBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a <= val)); }


void add(long[] bit, int pos, long val) {
  for (int x = pos; x < bit.length; x |= x + 1) {
    bit[x] += val;
  }
}
long sum(long[] bit, int pos) {
  long ret;
  for (int x = pos - 1; x >= 0; x = (x & (x + 1)) - 1) {
    ret += bit[x];
  }
  return ret;
}

int N;
int[] A;

int[][] G;
int Z;
int[] dis, fin;

void dfs(int u) {
  dis[u] = Z++;
  foreach (v; G[u]) {
    dfs(v);
  }
  fin[u] = Z++;
}

void main() {
  try {
    for (; ; ) {
      N = readInt();
      A = new int[N];
      foreach (v; 1 .. N) {
        A[v] = readInt();
      }
      
      G = new int[][N];
      foreach (v; 1 .. N) {
        G[A[v]] ~= v;
      }
      Z = 0;
      dis = new int[N];
      fin = new int[N];
      dfs(0);
      auto bit = new long[Z];
      long ans;
      foreach_reverse (u; 0 .. N) {
        ans += (bit.sum(fin[u]) - bit.sum(dis[u]));
        bit.add(dis[u], +1);
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}