#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <stdio.h>
using namespace std;
#define int long long
int MOD = 1000000007;
signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N, M, K;
	cin >> N >> M >> K;
	vector<int> L(M);
	vector<int> R(M);
	for (int i = 0; i < M; i++) {
		cin >> L[i] >> R[i];
	}
	vector<int> dp(N + 2, 0);
	dp[1] = 1;

	for (int i = 0; i < K; i++) {
		for (int j = 1; j <= N + 1; j++) {
			dp[j] = (dp[j] + dp[j - 1]) % MOD;
		}


		vector<int> ndp(N + 2, 0);
		for (int j = 0; j < M; j++) {
			int sum = dp[R[j]] - dp[L[j] - 1];
			if (sum < 0)sum += MOD;
			ndp[L[j]] = (ndp[L[j]] + sum) % MOD;
			ndp[R[j] + 1] -= sum; 
			if (ndp[R[j] + 1] < 0)ndp[R[j] + 1] += MOD;
		}
		for (int j = 1; j <= N + 1; j++) {
			ndp[j] = (ndp[j] + ndp[j - 1]) % MOD;
		}
		swap(dp, ndp);
	}

	cout << dp[N] << endl;
}