#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
ll const mod = 1e9+7;

#define p_ary(ary,a,b,i) do { cout << "["; for (int (i) = (a);(i) < (b);++(i)) cout << ary[(i)] << ((b)-1 == (i) ? "" : ", "); cout << "]\n"; } while(0)
#define p_map(map,it) do {cout << "{";for (auto (it) = map.begin();;++(it)) {if ((it) == map.end()) {cout << "}\n";break;}else cout << "" << (it)->first << "=>" << (it)->second << ", ";}}while(0)

int main() {
    int n,m,k;
    cin >> n >> m >> k;
    vector<int> l(m),r(m);
    for (int i = 0;i < m;++i) cin >> l[i] >> r[i];
    vector<vector<int>> dp(k+1,vector<int>(n+2,0));
    dp[0][1] = 1;
    for (int i = 0;i < k;++i) {
        for (int j = 0;j < n+1;++j) {
            dp[i][j+1] += dp[i][j];
            dp[i][j+1] %= mod;
        }
        for (int j = 0;j < m;++j) {
            int s = (dp[i][r[j]]-dp[i][l[j]-1])%mod;
            dp[i+1][l[j]] += s;
            dp[i+1][l[j]] %= mod;
            dp[i+1][r[j]+1] -= s;
            dp[i+1][r[j]+1] %= mod;
        }
        for (int j = 0;j < n+1;++j) {
            dp[i+1][j+1] += dp[i+1][j];
            dp[i+1][j+1] %= mod;
        }
    }
    cout << (dp[k][n]+mod)%mod << endl;
    return 0;
}