package adv2018; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Arrays; import java.util.InputMismatchException; public class Day18_7 { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int mod = 1000000007; long[][] C = new long[4000 + 1][4000 + 1]; for (int i = 0; i <= 4000; i++) { C[i][0] = 1; for (int j = 1; j <= i; j++) { C[i][j] = C[i - 1][j - 1] + C[i - 1][j]; if (C[i][j] >= mod) C[i][j] -= mod; } } int n = ni()+1; long[][] dp = new long[n][n]; for(int i = 0;i < n;i++){ dp[0][i] = 1; } // dp[0][2] = 1; long[][] ep = new long[n][n+1]; long[][] fp = new long[n][n+1]; long[][] gp = new long[n][n+1]; for(int i = 0;i < n;i++){ if(i < n-1){ for(int k = 0;k <= n;k++){ fp[i+1][k] += fp[i][k]; if(k-1 >= 0)fp[i+1][k-1] += fp[i][k]; fp[i+1][k] %= mod; if(k-1 >= 0)fp[i+1][k-1] %= mod; gp[i+1][k] += gp[i][k]; } } for(int k = 0;k < n;k++){ ep[i][k] += fp[i][k]; if(ep[i][k] >= mod)ep[i][k] -= mod; ep[i][k] += gp[i][k]; if(ep[i][k] >= mod)ep[i][k] -= mod; } for(int k = 0;k < n;k++){ if(k > 0){ ep[i][k] += ep[i][k-1]; if(ep[i][k] >= mod)ep[i][k] -= mod; } dp[i][k] += ep[i][k]; dp[i][k] %= mod; if(dp[i][k] == 0)continue; if(n+i-k >= 0 && n+i-k < n && k+1 <= n){ fp[n+i-k][k+1] += dp[i][k]; if(fp[n+i-k][k+1] >= mod)fp[n+i-k][k+1] -= mod; } if(i+1 < n){ gp[i+1][k+1] += dp[i][k]; if(gp[i+1][k+1] >= mod)gp[i+1][k+1] -= mod; } int lim = Math.min(n, n-k+i); if(lim < n){ gp[lim][k+1] -= dp[i][k]; if(gp[lim][k+1] < 0)gp[lim][k+1] += mod; } // for(int j = i+1;j < n && j <= n-1-k+i;j++){ // ep[j][k+1] += dp[i][k]; // if(ep[j][k+1] >= mod)ep[j][k+1] -= mod; // } } } out.println(dp[n-1][n-1]); } public static long pow(long a, long n, long mod) { // a %= mod; long ret = 1; int x = 63 - Long.numberOfLeadingZeros(n); for (; x >= 0; x--) { ret = ret * ret % mod; if (n << 63 - x < 0) ret = ret * a % mod; } return ret; } 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 Day18_7().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)); } }