#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint1000000007;
const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n, m, k; cin >> n >> m >> k;
	vector<int>l(m), r(m);
	rep(i, m) {
		cin >> l[i] >> r[i];
		l[i]--, r[i]--;
	}
	vector<mint>dp(n + 1);
	dp[0] = 1;
	rep(i, k) {
		vector<mint>sdp(n + 1);
		rep(j, n)sdp[j + 1] = sdp[j] + dp[j];
		vector<mint>ndp(n + 1);
		rep(j, m) {
			mint val = sdp[r[j] + 1] - sdp[l[j]];
			ndp[l[j]] += val;
			ndp[r[j] + 1] -= val;
		}
		rep(j, n)ndp[j + 1] += ndp[j];
		swap(dp, ndp);
	}
	cout << dp[n - 1].val() << endl;
	return 0;
}