#include <bits/stdc++.h>

using namespace std;

int main() {
    int N, M, K;
    
    cin>> N >> M >> K;
    
    vector<int> L(M), R(M);
    vector<vector<long long >> dp(3001, vector<long long>(3001, -1));
    
    for (int i = 0; i < M; i++)
        cin >> L[i] >> R[i];
        
    for (int i = 0; i < M; i++)
    	dp[K][i] = (N <= R[i]) ? 1 : 0;
    
    auto solve = [&](auto f, int k, int m) {
        if (dp[k][m] >= 0)
            return dp[k][m];
            
        long long r = 0LL;
        for (int i = 0; i < M; i++)
            if (min(R[m], R[i]) >= max(L[m], L[i]))
                r = (r + f(f, k + 1, i) * (min(R[m], R[i]) - max(L[m], L[i]) + 1) % 1000000007) % 1000000007;;
                    
        dp[k][m] = r;
        return r;
    };
    
    long long r = 0;
    
    for (int i = 0; i < M; i++)
        if (1 >= L[i])
        	r = (r + solve(solve, 1, i)) % 1000000007;
    
    cout << r << endl;
    
    return 0;
}