//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 0xccccccc;
const ll LINF = 0xcccccccccccccccLL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}

const unsigned int mod = 1000000007;
//const unsigned int mod = 998244353;

struct mint {
	unsigned int x;
	mint():x(0) {}
	mint(int64_t x_) {
		int64_t v = int64_t(x_ % mod);
		if(v < 0) v += mod;
		x = (unsigned int)v;
	}
	static mint row(int v) {
		mint v_;
		v_.x = v;
		return v_;
	}
	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) {
		uint64_t z = x;
		z *= a.x;
		x = (unsigned int)(z % 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;}
	friend bool operator==(const mint &a, const mint &b) {return a.x == b.x;}
	friend bool operator!=(const mint &a, const mint &b) {return a.x != b.x;}
	mint &operator++() {
		x++;
		if(x == mod) x = 0;
		return *this;
	}
	mint &operator--() {
		if(x == 0) x = mod;
		x--;
		return *this;
	}
	mint operator++(int) {
		mint result = *this;
		++*this;
		return result;
	}
	mint operator--(int) {
		mint result = *this;
		--*this;
		return result;
	}
	mint pow(int64_t t) const {
		mint x_ = *this, r = 1;
		while(t) {
			if(t&1) r *= x_;
			x_ *= x_;
			t >>= 1;
		}
		return r;
	}
	//for prime mod
	mint inv() const { return pow(mod-2);}
	mint& operator/=(const mint a) { return *this *= a.inv();}
	mint operator/(const mint a) {return mint(*this) /= a;}
};

struct combination {
	vector<mint> frac, ifrac;
	combination(int n):frac(n+1), ifrac(n+1) {
		assert(n < mod);
		frac[0] = 1;
		for (int i = 1; i <= n; ++i) frac[i] = frac[i-1]*i;
		ifrac[n] = frac[n].inv();
		for (int i = n; i >= 1; --i) ifrac[i-1] = ifrac[i]*i;
	}
	mint operator()(int n, int k) {
		if (k < 0 || k > n) return 0;
		return frac[n]*ifrac[k]*ifrac[n-k];
	}
} c(1000);

istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}

#define N 44

//head

int n, m, k;
P ab[N];
mint ans;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> m >> k;
	rep(i, m) cin >> ab[i];
	sort(ab, ab+m);
	rep(id, m) {
		vvi V;
		int cnt = 0;
		rep(i, m) {
			if(ab[i].second >= ab[id].second) {
				if(!V.empty() and ab[*V.back().begin()].first == ab[i].first) V.back().push_back(i);
				else V.push_back(vi(1, i));
				cnt++;
			}
		}
		int u = V.size();
		vector<vector<vector<mint>>> dp(u+1, vector<vector<mint>>(cnt+1, vector<mint>(n+1)));
		rep(i, n+1) {
			dp[0][0][i] = mint(ab[*V.begin()->begin()].first).pow(n-i)*c(n, i);
		}
		cnt = 0;
		rep(i, u) {
			int z = V[i].size();
			rep(j, cnt+1) rep(l, n+1) {
				rep(p, l+1) {
					int y = (i == u-1?k+1:ab[V[i+1][0]].first);
					if(y <= ab[id].first or j-p+z > 0) {
						dp[i+1][max(0, j-p+z)][l-p] += dp[i][j][l]*c(l, p)*mint(y-ab[V[i][0]].first).pow(p);
					}
					else break;
				}
			}
			cnt += z;
		}
		ans += mint(k+1).pow(n) * ab[id].second;
		rep(i, cnt+1) {
			ans -= dp[u][i][0] * ab[id].second;
		}
	}
	ans /= mint(k+1).pow(n);
	cout << ans << endl;
}