import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long MOD = (long)Math.pow(10, 9) + 7;
    int n = sc.nextInt();
    int m = sc.nextInt();
    int k = sc.nextInt();
    int[] L = new int[m];
    int[] R = new int[m];
    for(int i = 0; i < m; i++) {
      L[i] = sc.nextInt();
      R[i] = sc.nextInt();
    }
    long[][] dp = new long[k + 1][n + 1];
    dp[0][1] = 1;
    for(int i = 1; i < k + 1; i++) {
      long[] rui = new long[n + 1];
      for(int j = 1; j < n + 1; j++) {
        rui[j] = (rui[j - 1] + dp[i - 1][j]) % MOD;
      }
      long[] imos = new long[n + 1];
      for(int j = 0; j < m; j++) {
        long t = (MOD + rui[R[j]] - rui[L[j] - 1]) % MOD;
        imos[L[j]] = (imos[L[j]] + t) % MOD;
        if(R[j] < n) imos[R[j] + 1] = (MOD + imos[R[j] + 1] - t) % MOD;
      }
      for(int j = 1; j < n + 1; j++) {
        imos[j] = (imos[j - 1] + imos[j]) % MOD;
        dp[i][j] = imos[j];
      }
    }
    System.out.println(dp[k][n]);
  }
}