import java.io.*;
import java.util.*;


public class Main_yukicoder778 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		int[] a = new int[n - 1];
		for (int i = 0; i < n - 1; i++) {
			a[i] = sc.nextInt();
		}

		List<List<Integer>> edges = new ArrayList<>(n);
		for (int i = 0; i < n; i++) {
			edges.add(new ArrayList<>());
		}

		for (int i = 0; i < n - 1; i++) {
			edges.get(a[i]).add(i + 1);
		}
		
		BIT bit = new BIT(n);
		long ans = 0;
		
		boolean[] used = new boolean[n];
		Deque<Integer> st = new ArrayDeque<>();
		st.push(0);
		while (!st.isEmpty()) {
			int e = st.peek();
			
			if (used[e]) {
				st.pop();
				ans += bit.query(e);
				bit.add(e + 1, -1);
				continue;
			}

			used[e] = true;
			bit.add(e + 1, 1);
			for (int next : edges.get(e)) {
				st.push(next);
			}
		}

		pr.println(ans);
	}

	/**
	 * Binary Indexed Tree による Range Sum Query
	 */
	static class BIT {
		// [0,n-1]
		private int[] bit;
		private int n;

		/**
		 * n 個の要素を持つBITを生成する
		 * 
		 * @param n 要素数
		 */
		BIT(int n) {
			this.n = n;
			bit = new int[this.n];
		}

		/**
		 * i 番目の要素に x を足す
		 * 
		 * @param i 対象となる要素(1-indexed)
		 * @param x 追加する値
		 */
		void add(int i, int x) {
			while (i <= n) {
				bit[i - 1] += x;
				i += i & (-i);
			}
		}

		/**
		 * 指定した範囲の合計値を返す
		 * 
		 * @param i 範囲の上界。[1,i](1-indexed)
		 * @return 指定された範囲の合計値
		 */
		int query(int i) {
			int sum = 0;
			while (i > 0) {
				sum += bit[i - 1];
				i -= i & (-i);
			}

			return sum;
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);
			
		solve();
			
		pr.close();
		sc.close();
	}

	static class Scanner {
		BufferedReader br;

		Scanner (InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
		}

		private boolean isPrintable(int ch) {
			return ch >= '!' && ch <= '~';
		}

		private boolean isCRLF(int ch) {
			return ch == '\n' || ch == '\r' || ch == -1;
		}

		private int nextPrintable() {
			try {
				int ch;
				while (!isPrintable(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}

				return ch;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		String next() {
			try {
				int ch = nextPrintable();
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (isPrintable(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		int nextInt() {
			try {
				// parseInt from Integer.parseInt()
				boolean negative = false;
				int res = 0;
				int limit = -Integer.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Integer.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				int multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		long nextLong() {
			try {
				// parseLong from Long.parseLong()
				boolean negative = false;
				long res = 0;
				long limit = -Long.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Long.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				long multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		float nextFloat() {
			return Float.parseFloat(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			try {
				int ch;
				while (isCRLF(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (!isCRLF(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		void close() {
			try {
				br.close();
			} catch (IOException e) {
//				throw new NoSuchElementException();
			}
		}
	}

	static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}