//#include <atcoder/all>
#include <iostream> // cout, endl, cin
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <cstdio> // printf
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set
#include <stack> // stack
#include <deque> // deque
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <bitset> // bitset
#include <cctype> // isupper, islower, isdigit, toupper, tolower
#include<math.h>
#include <iomanip>
using namespace std;
//using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repi(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
typedef long long ll;
typedef unsigned long long ull;
const ll inf=1e18;
//g++ main.cpp -std=c++14 -I .  
 
ll pow_pow(ll x,ll n,ll mod){
    if(n==0) return 1;
    x%=mod;
    ll res=pow_pow(x*x%mod,n/2,mod);
    if(n&1)res=res*x%mod;
    return res;
}
 
struct UnionFind {
    vector<int> par, siz;
    UnionFind(int n) : par(n, -1) , siz(n, 1) { }
    int root(int x) {
        if (par[x] == -1) return x;
        else return par[x] = root(par[x]);
    }
    bool issame(int x, int y) {
        return root(x) == root(y);
    }
    bool unite(int x, int y) {
        x = root(x), y = root(y);
        if (x == y) return false; 
        if (siz[x] < siz[y]) swap(x, y);
        par[y] = x;
        siz[x] += siz[y];
        return true;
    }
    int size(int x) {
        return siz[root(x)];
    }
};

int gcd(int x,int y){
    if(y==0)return x;
    return gcd(y,x%y);
}

ll lcm(ll x,ll y){
    return ll(x/gcd(x,y))*y;
}
 
 
 
 
template<class T> bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    else return false;
}
template<class T> bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    else return false;
}
 
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
const ll mod =1e9+7;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
 
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
// combination mod prime
// https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619
struct combination {
  vector<mint> fact, ifact;
  combination(int n):fact(n+1),ifact(n+1) {
    //assert(n < mod);
    fact[0] = 1;
    for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(int n, int k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
  mint p(int n, int k) {
    return fact[n]*ifact[n-k];
  }
} c(1000005);
 
 
ll sqrt_(ll x) {
  ll l = 0, r = ll(3e9)+1;
  while (l+1<r) {
    ll c = (l+r)/2;
    if (c*c <= x) l = c; else r = c;
  }
  return l;
}


int valid(int x,int y,int h,int w){
  if(x>=0 && y>=0 && x<h && y<w)return 1;
  else return 0;
}
 
int vx[]={0,1,0,-1},vy[]={1,0,-1,0};
ll comb[51][51];

void init_comb(){
  comb[0][0]=1;
  for(int i=1; i<=50; i++){
    for(int j=0; j<=i; j++){
      if(j==0 || j==i)comb[i][j]=1;
      else comb[i][j]=comb[i-1][j]+comb[i-1][j-1];
    }
  }
}

//ll nCk(int n,int k){
 // return comb[n][k];
//}

struct edge{
  int to; ll w;
  edge(int to,ll w) : to(to),w(w) {}
};

using graph = vector<vector<int> > ;
using P= pair<ll,ll>;

//string T="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
//string S="abcdefghijklmnopqrstuvwxyz";


void comp(vector<int>&a){
  set<int>s(a.begin(),a.end());
  int cnt=0;
  map<ll,ll>d;
  for(auto y:s)d[y]=cnt++;
  for(auto&y:a)y=d[y];
}


int main(){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
  int n,m,k; cin >> n >> m >> k;
  vector<int> l(m),r(m);
  rep(i,m)cin >> l[i] >> r[i];
  vector<vector<mint> > dp(k+1,vector<mint>(n+2)),sum(k+1,vector<mint>(n+2));
  dp[0][1]=1;
  dp[0][2]=-1;
  rep(i,k+1){
    repi(j,1,n+2)dp[i][j]+=dp[i][j-1];
    repi(j,1,n+2)sum[i][j]=sum[i][j-1]+dp[i][j];
    if(i+1>k)break;
    rep(j,m){
      mint now=sum[i][r[j]]-sum[i][l[j]-1];
      dp[i+1][r[j]+1]-=now;
      dp[i+1][l[j]]+=now;
    }
  }
  cout << dp[k][n] << endl;
  
}