package yukicoder._1285; import java.io.IOException; import java.io.InputStream; import java.io.PrintStream; import java.io.PrintWriter; import java.io.UncheckedIOException; import java.lang.reflect.Array; import java.util.Arrays; import java.util.Objects; public class Main { public void exec() { int n = stdin.nextInt(); int[] a = stdin.nextIntArray(n); Arrays.sort(a); int ans = 1; for (int i = 0; i < n - 1; i++) { if (!(a[i]+1 < a[i+1])) { ans++; } } stdout.println(ans); } private static final Stdin stdin = new Stdin(System.in); private static final Stdout stdout = new Stdout(System.out); private static final Stderr stderr = new Stderr(System.err, false); public static void main(String[] args) { try { new Main().exec(); } finally { stdout.flush(); } } // ASCII ONLY public static class Stdin { private InputStream in; private byte[] buf; private int ptr; private int len; public Stdin(InputStream in) { this.in = in; this.buf = new byte[1024]; this.ptr = 0; this.len = 0; } public String nextString() { StringBuilder sb = new StringBuilder(); byte b; while ((b = read()) != -1) { sb.appendCodePoint(b); } return sb.toString(); } public int nextInt() { return (int)nextLong(); } public double nextDouble() { return Double.parseDouble(nextString()); } public long nextLong() { boolean negative = false; int x = 0; byte b = read(); if (b == '-') { negative = true; } else { x += b-'0'; } while ((b=read()) != -1) { x *= 10; x += b-'0'; } return negative ? -x : x; } private byte read() { byte b = readByte(); if (b == '\r') { readByte(); // LFを読み飛ばす return -1; } else if (b == '\n' || b == ' ') { return -1; } else { return b; } } private byte readByte(){ if (len == ptr) { try { ptr = 0; len = in.read(buf); if (len == -1) return -1; } catch (IOException e) { throw new UncheckedIOException(e); } } return buf[ptr++]; } public String[] nextStringArray(int n) { String[] a = new String[n]; for (int i = 0; i < n; i++) a[i] = nextString(); return a; } public int[] nextIntArray(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) a[i] = nextInt(); return a; } public double[] nextDoubleArray(int n) { double[] a = new double[n]; for (int i = 0; i < n; i++) a[i] = nextDouble(); return a; } public long[] nextLongArray(int n) { long[] a = new long[n]; for (int i = 0; i < n; i++) a[i] = nextLong(); return a; } } public static class Stdout { private PrintWriter stdout; public Stdout(PrintStream stdout) { this.stdout = new PrintWriter(stdout, false); } public void println(Object ... objs) { for (int i = 0, len = objs.length; i < len; i++) { stdout.print(objs[i]); if (i != len-1) stdout.print(' '); } stdout.println(); } public void flush() { stdout.flush(); } } public static class Stderr { private PrintWriter stderr; private boolean debug; public Stderr(PrintStream stderr, boolean debug) { this.stderr = new PrintWriter(stderr, false); this.debug = debug; } public void println(Object ... objs) { if (!debug) return ; stderr.print("DEBUG: "); for (int i = 0, len = objs.length; i < len; i++) { stderr.print(deepToString(objs[i])); if (i != len-1) stderr.print(' '); } stderr.println(); stderr.flush(); } private String deepToString(Object o) { if (o == null) { return "null"; } // 配列の場合 if (o.getClass().isArray()) { int len = Array.getLength(o); String[] tokens = new String[len]; for (int i = 0; i < len; i++) { tokens[i] = deepToString(Array.get(o, i)); } return "{" + String.join(", ", tokens) + "}"; } return Objects.toString(o); } } }