class SegmentTreeRSQ { public int M, H, N; public long[] st; public long[] plus; public SegmentTreeRSQ(int n) { N = n; M = Integer.highestOneBit(Math.max(N - 1, 1)) << 2; H = M >>> 1; st = new long[M]; plus = new long[H]; } public SegmentTreeRSQ(int[] a) { N = a.length; M = Integer.highestOneBit(Math.max(N - 1, 1)) << 2; H = M >>> 1; st = new long[M]; plus = new long[H]; for (int i = 0; i < N; i++) { st[H + i] = a[i]; } for (int i = (M >> 1) - 1; i >= 1; i--) { propagate(i); } } public void add(int pos, int v) { for (int i = H + pos; i >= 1; i >>>= 1) { st[i] += v; } } private void propagate(int i) { int count = H / Integer.highestOneBit(i); st[i] = st[2 * i] + st[2 * i + 1] + plus[i] * count; } public void add(int l, int r, int v) { if (l < r) add(l, r, v, 0, H, 1); } private void add(int l, int r, int v, int cl, int cr, int cur) { if (cur >= H) { st[cur] += v; } else if (l <= cl && cr <= r) { plus[cur] += v; propagate(cur); } else { int mid = cl + cr >>> 1; if (cl < r && l < mid) { add(l, r, v, cl, mid, 2 * cur); } if (mid < r && l < cr) { add(l, r, v, mid, cr, 2 * cur + 1); } propagate(cur); } } private long gsum; public long sum(int l, int r) { gsum = 0; sum(l, r, 0, H, 1); return gsum; } private void sum(int l, int r, int cl, int cr, int cur) { if (l <= cl && cr <= r) { gsum += st[cur]; } else { int mid = cl + cr >>> 1; if (cl < r && l < mid) { sum(l, r, cl, mid, 2 * cur); } if (mid < r && l < cr) { sum(l, r, mid, cr, 2 * cur + 1); } gsum += plus[cur] * (Math.min(r, cr) - Math.max(l, cl)); } } } public class Main { private static void solve() { int n = ni(); int m = ni(); int k = ni(); int[][] r = ntable(m, 2); SegmentTreeRSQ[] st = new SegmentTreeRSQ[k + 1]; st[0] = new SegmentTreeRSQ(n + 1); int mod = (int) 1e9 + 7; st[0].add(1, 1); for (int i = 0; i < k; i++) { st[i + 1] = new SegmentTreeRSQ(n + 1); for (int[] p : r) { int sum = (int) (st[i].sum(p[0], p[1] + 1) % mod); st[i + 1].add(p[0], p[1] + 1, sum); } } System.out.println(st[k].sum(n, n + 1) % mod); } public static void main(String[] args) { new Thread(null, new Runnable() { @Override public void run() { long start = System.currentTimeMillis(); String debug = args.length > 0 ? args[0] : null; if (debug != null) { try { is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug)); } catch (Exception e) { throw new RuntimeException(e); } } reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768); solve(); out.flush(); tr((System.currentTimeMillis() - start) + "ms"); } }, "", 64000000).start(); } private static java.io.InputStream is = System.in; private static java.io.PrintWriter out = new java.io.PrintWriter(System.out); private static java.util.StringTokenizer tokenizer = null; private static java.io.BufferedReader reader; public static String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) { try { tokenizer = new java.util.StringTokenizer(reader.readLine()); } catch (Exception e) { throw new RuntimeException(e); } } return tokenizer.nextToken(); } private static double nd() { return Double.parseDouble(next()); } private static long nl() { return Long.parseLong(next()); } private static int[] na(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) a[i] = ni(); return a; } private static char[] ns() { return next().toCharArray(); } private static long[] nal(int n) { long[] a = new long[n]; for (int i = 0; i < n; i++) a[i] = nl(); return a; } private static int[][] ntable(int n, int m) { int[][] table = new int[n][m]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[i][j] = ni(); } } return table; } private static int[][] nlist(int n, int m) { int[][] table = new int[m][n]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[j][i] = ni(); } } return table; } private static int ni() { return Integer.parseInt(next()); } private static void tr(Object... o) { if (is != System.in) System.out.println(java.util.Arrays.deepToString(o)); } }