package af2019; 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 N3046 { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int K = ni(); int n = ni(); int[] x = na(n); long[] P = new long[100001]; P[0] = 1; for(int v : x) { P[v] = mod-1; } out.println(inv(P)[K]); } public static final int[] NTTPrimes = {1053818881, 1051721729, 1045430273, 1012924417, 1007681537, 1004535809, 998244353, 985661441, 976224257, 975175681}; public static final int[] NTTPrimitiveRoots = {7, 6, 3, 5, 3, 3, 3, 3, 3, 17}; // public static final int[] NTTPrimes = {1012924417, 1004535809, 998244353, 985661441, 975175681, 962592769, 950009857, 943718401, 935329793, 924844033}; // public static final int[] NTTPrimitiveRoots = {5, 3, 3, 3, 17, 7, 7, 7, 3, 5}; public static long[] convoluteSimply(long[] a, long[] b, int P, int g) { int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2); long[] fa = nttmb(a, m, false, P, g); long[] fb = a == b ? fa : nttmb(b, m, false, P, g); for(int i = 0;i < m;i++){ fa[i] = fa[i]*fb[i]%P; } return nttmb(fa, m, true, P, g); } public static long[] convolute(long[] a, long[] b) { int USE = 2; int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2); long[][] fs = new long[USE][]; for(int k = 0;k < USE;k++){ int P = NTTPrimes[k], g = NTTPrimitiveRoots[k]; long[] fa = nttmb(a, m, false, P, g); long[] fb = a == b ? fa : nttmb(b, m, false, P, g); for(int i = 0;i < m;i++){ fa[i] = fa[i]*fb[i]%P; } fs[k] = nttmb(fa, m, true, P, g); } int[] mods = Arrays.copyOf(NTTPrimes, USE); long[] gammas = garnerPrepare(mods); int[] buf = new int[USE]; for(int i = 0;i < fs[0].length;i++){ for(int j = 0;j < USE;j++)buf[j] = (int)fs[j][i]; long[] res = garnerBatch(buf, mods, gammas); long ret = 0; for(int j = res.length-1;j >= 0;j--)ret = ret * mods[j] + res[j]; fs[0][i] = ret; } return fs[0]; } public static long[] convolute(long[] a, long[] b, int USE, int mod) { int m = Math.max(2, Integer.highestOneBit(Math.max(a.length, b.length)-1)<<2); long[][] fs = new long[USE][]; for(int k = 0;k < USE;k++){ int P = NTTPrimes[k], g = NTTPrimitiveRoots[k]; long[] fa = nttmb(a, m, false, P, g); long[] fb = a == b ? fa : nttmb(b, m, false, P, g); for(int i = 0;i < m;i++){ fa[i] = fa[i]*fb[i]%P; } fs[k] = nttmb(fa, m, true, P, g); } int[] mods = Arrays.copyOf(NTTPrimes, USE); long[] gammas = garnerPrepare(mods); int[] buf = new int[USE]; for(int i = 0;i < fs[0].length;i++){ for(int j = 0;j < USE;j++)buf[j] = (int)fs[j][i]; long[] res = garnerBatch(buf, mods, gammas); long ret = 0; for(int j = res.length-1;j >= 0;j--)ret = (ret * mods[j] + res[j]) % mod; fs[0][i] = ret; } return fs[0]; } // static int[] wws = new int[270000]; // outer faster // Modifed Montgomery + Barrett private static long[] nttmb(long[] src, int n, boolean inverse, int P, int g) { long[] dst = Arrays.copyOf(src, n); int h = Integer.numberOfTrailingZeros(n); long K = Integer.highestOneBit(P)<<1; int H = Long.numberOfTrailingZeros(K)*2; long M = K*K/P; int[] wws = new int[1<= 2*P)dst[s] -= 2*P; // long Q = (u&(1L<<32)-1)*J&(1L<<32)-1; long Q = (u<<32)*J>>>32; dst[t] = (u>>>32)-(Q*P>>>32)+P; } } if(i < h-1){ for(int k = 0;k < 1<= P)dst[i] -= P; } for(int i = 0;i < n;i++){ int rev = Integer.reverse(i)>>>-h; if(i < rev){ long d = dst[i]; dst[i] = dst[rev]; dst[rev] = d; } } if(inverse){ long in = invl(n, P); for(int i = 0;i < n;i++)dst[i] = modh(dst[i]*in, M, H, P); } return dst; } // Modified Shoup + Barrett private static long[] nttsb(long[] src, int n, boolean inverse, int P, int g) { long[] dst = Arrays.copyOf(src, n); int h = Integer.numberOfTrailingZeros(n); long K = Integer.highestOneBit(P)<<1; int H = Long.numberOfTrailingZeros(K)*2; long M = K*K/P; long dw = inverse ? pow(g, P-1-(P-1)/n, P) : pow(g, (P-1)/n, P); long[] wws = new long[1<= 2*P)ndsts -= 2*P; long T = dst[s] - dst[t] + 2*P; long Q = wws[k]*T>>>32; dst[s] = ndsts; dst[t] = ws[k]*T-Q*P&(1L<<32)-1; } } // dw = dw * dw % P; if(i < h-1){ for(int k = 0;k < 1<= P)dst[i] -= P; } for(int i = 0;i < n;i++){ int rev = Integer.reverse(i)>>>-h; if(i < rev){ long d = dst[i]; dst[i] = dst[rev]; dst[rev] = d; } } if(inverse){ long in = invl(n, P); for(int i = 0;i < n;i++){ dst[i] = modh(dst[i] * in, M, H, P); } } return dst; } static final long mask = (1L<<31)-1; public static long modh(long a, long M, int h, int mod) { long r = a-((M*(a&mask)>>>31)+M*(a>>>31)>>>h-31)*mod; return r < mod ? r : r-mod; } private static long[] garnerPrepare(int[] m) { int n = m.length; assert n == m.length; if(n == 0)return new long[0]; long[] gamma = new long[n]; for(int k = 1;k < n;k++){ long prod = 1; for(int i = 0;i < k;i++){ prod = prod * m[i] % m[k]; } gamma[k] = invl(prod, m[k]); } return gamma; } private static long[] garnerBatch(int[] u, int[] m, long[] gamma) { int n = u.length; assert n == m.length; long[] v = new long[n]; v[0] = u[0]; for(int k = 1;k < n;k++){ long temp = v[k-1]; for(int j = k-2;j >= 0;j--){ temp = (temp * m[j] + v[j]) % m[k]; } v[k] = (u[k] - temp) * gamma[k] % m[k]; if(v[k] < 0)v[k] += m[k]; } return v; } public static int mod = 1000000007; public static long[] mul(long[] a, long[] b) { if(Math.max(a.length, b.length) >= 3000){ return Arrays.copyOf(convolute(a, b, 3, mod), a.length+b.length-1); }else{ return mulnaive(a, b); } } public static long[] mul(long[] a, long[] b, int lim) { if(Math.max(a.length, b.length) >= 3000){ return Arrays.copyOf(convolute(a, b, 3, mod), lim); }else{ return mulnaive(a, b, lim); } } public static long[] mulnaive(long[] a, long[] b) { long[] c = new long[a.length+b.length-1]; long big = 8L*mod*mod; for(int i = 0;i < a.length;i++){ for(int j = 0;j < b.length;j++){ c[i+j] += a[i]*b[j]; if(c[i+j] >= big)c[i+j] -= big; } } for(int i = 0;i < c.length;i++)c[i] %= mod; return c; } public static long[] mulnaive(long[] a, long[] b, int lim) { long[] c = new long[lim]; long big = 8L*mod*mod; for(int i = 0;i < a.length;i++){ for(int j = 0;j < b.length && i+j < lim;j++){ c[i+j] += a[i]*b[j]; if(c[i+j] >= big)c[i+j] -= big; } } for(int i = 0;i < c.length;i++)c[i] %= mod; return c; } public static long[] add(long[] a, long[] b) { long[] c = new long[Math.max(a.length, b.length)]; for(int i = 0;i < a.length;i++)c[i] += a[i]; for(int i = 0;i < b.length;i++)c[i] += b[i]; for(int i = 0;i < c.length;i++)if(c[i] >= mod)c[i] -= mod; return c; } public static long[] add(long[] a, long[] b, int lim) { long[] c = new long[lim]; for(int i = 0;i < a.length && i < lim;i++)c[i] += a[i]; for(int i = 0;i < b.length && i < lim;i++)c[i] += b[i]; for(int i = 0;i < c.length;i++)if(c[i] >= mod)c[i] -= mod; return c; } public static long[] sub(long[] a, long[] b) { long[] c = new long[Math.max(a.length, b.length)]; for(int i = 0;i < a.length;i++)c[i] += a[i]; for(int i = 0;i < b.length;i++)c[i] -= b[i]; for(int i = 0;i < c.length;i++)if(c[i] < 0)c[i] += mod; return c; } public static long[] sub(long[] a, long[] b, int lim) { long[] c = new long[lim]; for(int i = 0;i < a.length && i < lim;i++)c[i] += a[i]; for(int i = 0;i < b.length && i < lim;i++)c[i] -= b[i]; for(int i = 0;i < c.length;i++)if(c[i] < 0)c[i] += mod; return c; } // F_{t+1}(x) = -F_t(x)^2*P(x) + 2F_t(x) // if want p-destructive, comment out flipping p just before returning. public static long[] inv(long[] p) { int n = p.length; long[] f = {invl(p[0], mod)}; for(int i = 0;i < p.length;i++){ if(p[i] == 0)continue; p[i] = mod-p[i]; } for(int i = 1;i < 2*n;i*=2){ long[] f2 = mul(f, f, Math.min(n, 2*i)); long[] f2p = mul(f2, Arrays.copyOf(p, i), Math.min(n, 2*i)); for(int j = 0;j < f.length;j++){ f2p[j] += 2L*f[j]; if(f2p[j] >= mod)f2p[j] -= mod; if(f2p[j] >= mod)f2p[j] -= mod; } f = f2p; } for(int i = 0;i < p.length;i++){ if(p[i] == 0)continue; p[i] = mod-p[i]; } return f; } // differentiate public static long[] d(long[] p) { long[] q = new long[p.length]; for(int i = 0;i < p.length-1;i++){ q[i] = p[i+1] * (i+1) % mod; } return q; } // integrate public static long[] i(long[] p) { long[] q = new long[p.length]; for(int i = 0;i < p.length-1;i++){ q[i+1] = p[i] * invl(i+1, mod) % mod; } return q; } // F_{t+1}(x) = F_t(x)-(ln F_t(x) - P(x)) * F_t(x) public static long[] exp(long[] p) { int n = p.length; long[] f = {p[0]}; for(int i = 1;i < 2*n;i*=2){ long[] ii = ln(f); long[] sub = sub(ii, p, Math.min(n, 2*i)); if(--sub[0] < 0)sub[0] += mod; for(int j = 0;j < 2*i && j < n;j++){ sub[j] = mod-sub[j]; if(sub[j] == mod)sub[j] = 0; } f = mul(sub, f, Math.min(n, 2*i)); // f = sub(f, mul(sub(ii, p, 2*i), f, 2*i)); } return f; } // \int f'(x)/f(x) dx public static long[] ln(long[] f) { long[] ret = i(mul(d(f), inv(f))); ret[0] = f[0]; return ret; } // ln F(x) - k ln P(x) = 0 public static long[] pow(long[] p, int K) { int n = p.length; long[] lnp = ln(p); for(int i = 1;i < lnp.length;i++)lnp[i] = lnp[i] * K % mod; lnp[0] = pow(p[0], K, mod); // go well for some reason return exp(Arrays.copyOf(lnp, n)); } // destructive public static long[] divf(long[] a, int[][] fif) { for(int i = 0;i < a.length;i++)a[i] = a[i] * fif[1][i] % mod; return a; } // destructive public static long[] mulf(long[] a, int[][] fif) { for(int i = 0;i < a.length;i++)a[i] = a[i] * fif[0][i] % mod; return a; } public static long[] transformExponentially(long[] a, int[][] fif) { return mulf(exp(divf(Arrays.copyOf(a, a.length), fif)), fif); } public static long[] transformLogarithmically(long[] a, int[][] fif) { return mulf(Arrays.copyOf(ln(divf(Arrays.copyOf(a, a.length), fif)), a.length), fif); } // 1/(1-F)-1 static long[] transformInvertly(long[] a) { long[] b = new long[a.length]; for(int i = 0;i < a.length;i++){ b[i] = mod - a[i]; if(b[i] == mod)b[i] = 0; } if(++b[0] == mod)b[0] = 0; long[] ret = inv(b); if(--ret[0] < 0)ret[0] += mod; return ret; } // -1/(1+F)+1 static long[] transformInverseOfInvertly(long[] a) { long[] b = new long[a.length]; for(int i = 0;i < a.length;i++){ b[i] = a[i]; } if(++b[0] == mod)b[0] = 0; long[] ret = inv(b); for(int i = 0;i < a.length;i++){ ret[i] = mod - ret[i]; if(ret[i] == mod)ret[i] = 0; } if(++ret[0] == mod)ret[0] = 0; return ret; } 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; } public static long invl(long a, long mod) { long b = mod; long p = 1, q = 0; while (b > 0) { long c = a / b; long d; d = a; a = b; b = d % b; d = p; p = q; q = d - c * q; } return p < 0 ? p + mod : p; } public static long[] reverse(long[] p) { long[] ret = new long[p.length]; for(int i = 0;i < p.length;i++){ ret[i] = p[p.length-1-i]; } return ret; } public static long[] reverse(long[] p, int lim) { long[] ret = new long[lim]; for(int i = 0;i < lim && i < p.length;i++){ ret[i] = p[p.length-1-i]; } return ret; } // [quotient, remainder] // remainder can be empty. // @see http://www.dis.uniroma1.it/~sankowski/lecture4.pdf public static long[][] div(long[] p, long[] q) { if(p.length < q.length)return new long[][]{new long[0], Arrays.copyOf(p, p.length)}; long[] rp = reverse(p, p.length-q.length+1); long[] rq = reverse(q, p.length-q.length+1); long[] rd = mul(rp, inv(rq), p.length-q.length+1); long[] d = reverse(rd, p.length-q.length+1); long[] r = sub(p, mul(d, q, q.length-1), q.length-1); return new long[][]{d, r}; } 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 N3046().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)); } }