package gioku2020day1; 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 M { InputStream is; PrintWriter out; String INPUT = ""; void solve() { int n = ni(), m = ni(); int[] from = new int[m]; int[] to = new int[m]; for(int i = 0;i < m;i++){ from[i] = ni()-1; to[i] = ni()-1; } int[] hey = new int[2*m]; for(int i = 0;i < m;i++){ hey[i] =from[i]; hey[i+m] = to[i]; } int[] imap = shrinkX(hey); long ans = (long)n*(n+1)/2; for(int v : imap){ ans -= v+1; } for(int i = 0;i < m;i++){ from[i] = hey[i]; to[i] = hey[i+m]; } int w = imap.length; int[][] g = packD(w, to, from); int[] clus = decomposeToSCCNoRec(g); int[][] cg = condense(g, clus); int u = cg.length; int[] maxs = new int[u]; for(int i = 0;i < w;i++){ maxs[clus[i]] = Math.max(maxs[clus[i]], imap[i]); } for(int i = u-1;i >= 0;i--){ for(int e : cg[i]){ maxs[e] = Math.max(maxs[e], maxs[i]); } } for(int i = 0;i < w;i++){ ans += maxs[clus[i]] + 1; } out.println(ans); } public static int[] shrinkX(int[] a) { int n = a.length; long[] b = new long[n]; for (int i = 0; i < n; i++) b[i] = (long) a[i] << 32 | i; Arrays.sort(b); int[] ret = new int[n]; int p = 0; ret[0] = (int) (b[0] >> 32); for (int i = 0; i < n; i++) { if (i > 0 && (b[i] ^ b[i - 1]) >> 32 != 0) { p++; ret[p] = (int) (b[i] >> 32); } a[(int) b[i]] = p; } return Arrays.copyOf(ret, p + 1); } public static int[] decomposeToSCCNoRec(int[][] g) { int n = g.length; int[] stack = new int[n+1]; int[] ind = new int[n+1]; int[] ord = new int[n]; Arrays.fill(ord, -1); int[] low = new int[n]; Arrays.fill(low, -1); int sp = 0; int id = 0; // preorder int[] clus = new int[n]; int cid = 0; int[] cstack = new int[n+1]; int csp = 0; boolean[] incstack = new boolean[n]; for(int i = 0;i < n;i++){ if(ord[i] == -1){ ind[sp] = 0; cstack[csp++] = i; stack[sp++] = i; incstack[i] = true; while(sp > 0){ int cur = stack[sp-1]; if(ind[sp-1] == 0){ ord[cur] = low[cur] = id++; } if(ind[sp-1] < g[cur].length){ int nex = g[cur][ind[sp-1]]; if(ord[nex] == -1){ ind[sp-1]++; ind[sp] = 0; incstack[nex] = true; cstack[csp++] = nex; stack[sp++] = nex; }else{ // shortcut // U.tr(cur, nex, incstack[nex], low[nex], stack); if(incstack[nex])low[cur] = Math.min(low[cur], ord[nex]); // low is ok too, but slower. ind[sp-1]++; } }else{ if(ord[cur] == low[cur]){ while(csp > 0){ incstack[cstack[csp-1]] = false; clus[cstack[--csp]] = cid; if(cstack[csp] == cur)break; } cid++; } if(--sp >= 1)low[stack[sp-1]] = Math.min(low[stack[sp-1]], low[stack[sp]]); } } } } return clus; } public static int[][] condense(int[][] g, int[] clus) { int n = g.length; int m = 0; for(int i = 0;i < n;i++)m = Math.max(m, clus[i]); m++; int[] cp = new int[m]; for(int i = 0;i < n;i++){ cp[clus[i]] += g[i].length; } int[][] c = new int[m][]; for(int i = 0;i < m;i++){ c[i] = new int[cp[i]]; } for(int i = 0;i < n;i++){ for(int j = 0;j < g[i].length;j++){ c[clus[i]][--cp[clus[i]]] = clus[g[i][j]]; } } for(int i = 0;i < m;i++){ Arrays.sort(c[i]); int jp = 0; for(int j = 0;j < c[i].length;j++){ if((j == 0 || c[i][j] != c[i][j-1]) && c[i][j] != i){ c[i][jp++] = c[i][j]; } } c[i] = Arrays.copyOf(c[i], jp); } return c; } static int[][] packD(int n, int[] from, int[] to) { int[][] g = new int[n][]; int[] p = new int[n]; for (int f : from) p[f]++; for (int i = 0; i < n; i++) g[i] = new int[p[i]]; for (int i = 0; i < from.length; i++) { g[from[i]][--p[from[i]]] = to[i]; } return g; } 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 M().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)); } }