package contest181005; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Arrays; import java.util.Comparator; import java.util.InputMismatchException; public class D { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int n = ni(); int[][] rs = new int[n][]; for(int i = 0;i < n;i++) { rs[i] = new int[] {i+1, ni()}; } int[][] fs = new int[n][]; int[][] bs = new int[n][]; int pf = 0, pb = 0; for(int i = 0;i < n;i++) { if(rs[i][0] <= rs[i][1]) { fs[pf++] = rs[i]; }else { bs[pb++] = rs[i]; } Arrays.sort(rs[i]); } fs = Arrays.copyOf(fs, pf); bs = Arrays.copyOf(bs, pb); int[] fst = new int[fs.length]; for(int i = 0;i < fst.length;i++)fst[i] = fs[i][0]; int[] fen = new int[fs.length]; for(int i = 0;i < fen.length;i++)fen[i] = fs[i][1]; Arrays.sort(fst); Arrays.sort(fen); long ans = 0; for(int[] b : bs) { ans += lowerBound(fst, b[1]+1) - lowerBound(fen, b[0]); } for(int[] b : bs) { b[0] = 35000 - b[0]; b[1] = 35000 - b[1]; Arrays.sort(b); } ans += count(fs) + count(bs); out.println(ans); } long count(int[][] fs) { int n = fs.length; Arrays.sort(fs, new Comparator() { public int compare(int[] a, int[] b) { return a[0] - b[0]; } }); long ret = 0; int[] ft = new int[40000]; for(int i = n-1;i >= 0;i--) { ret += sumFenwick(ft, fs[i][1]); addFenwick(ft, fs[i][1], 1); } return ret; } public static int sumFenwick(int[] ft, int i) { int sum = 0; for(i++;i > 0;i -= i&-i)sum += ft[i]; return sum; } public static void addFenwick(int[] ft, int i, int v) { if(v == 0 || i < 0)return; int n = ft.length; for(i++;i < n;i += i&-i)ft[i] += v; } public static int lowerBound(int[] a, int v){ return lowerBound(a, 0, a.length, v); } public static int lowerBound(int[] a, int l, int r, int v) { if(l > r || l < 0 || r > a.length)throw new IllegalArgumentException(); int low = l-1, high = r; while(high-low > 1){ int h = high+low>>>1; if(a[h] >= v){ high = h; }else{ low = h; } } return high; } void run() throws Exception { is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes()); out = new PrintWriter(System.out); long s = System.currentTimeMillis(); solve(); out.flush(); if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms"); // Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){ // @Override // public void run() { // long s = System.currentTimeMillis(); // solve(); // out.flush(); // if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms"); // } // }; // t.start(); // t.join(); } public static void main(String[] args) throws Exception { new D().run(); } private byte[] inbuf = new byte[1024]; public int lenbuf = 0, ptrbuf = 0; private int readByte() { if(lenbuf == -1)throw new InputMismatchException(); if(ptrbuf >= lenbuf){ ptrbuf = 0; try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); } if(lenbuf <= 0)return -1; } return inbuf[ptrbuf++]; } private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); } private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; } private double nd() { return Double.parseDouble(ns()); } private char nc() { return (char)skip(); } private String ns() { int b = skip(); StringBuilder sb = new StringBuilder(); while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ') sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } private char[] ns(int n) { char[] buf = new char[n]; int b = skip(), p = 0; while(p < n && !(isSpaceChar(b))){ buf[p++] = (char)b; b = readByte(); } return n == p ? buf : Arrays.copyOf(buf, p); } private int[] na(int n) { int[] a = new int[n]; for(int i = 0;i < n;i++)a[i] = ni(); return a; } private long[] nal(int n) { long[] a = new long[n]; for(int i = 0;i < n;i++)a[i] = nl(); return a; } private char[][] nm(int n, int m) { char[][] map = new char[n][]; for(int i = 0;i < n;i++)map[i] = ns(m); return map; } private int[][] nmi(int n, int m) { int[][] map = new int[n][]; for(int i = 0;i < n;i++)map[i] = na(m); return map; } private int ni() { return (int)nl(); } private long nl() { long num = 0; int b; boolean minus = false; while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-')); if(b == '-'){ minus = true; b = readByte(); } while(true){ if(b >= '0' && b <= '9'){ num = num * 10 + (b - '0'); }else{ return minus ? -num : num; } b = readByte(); } } private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); } }