#include <bits/stdc++.h>

using namespace std;

#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

struct BigInteger {
	static const ll LogBase = 8;
	static const ll BASE = pow(10, LogBase);
	vector<ll> dig;
	bool isNeg;
	BigInteger() {}
	BigInteger(ll a, int sz, bool negative = false) : dig(sz, a), isNeg(negative) {}
	BigInteger(string s) {
		if (s[0] == '-') {
			isNeg = true;
			s = s.substr(1);
		} else isNeg = false;
		reverse(all(s));
		for (int i = 0; i < s.size(); i += LogBase) {
			dig.pb(0);
			ll p = 1;
			for (int j = 0; j < LogBase; j++) {
				if (i + j >= s.size()) break;
				dig.back() = dig.back() + (s[i + j] - '0') * p;
				p *= 10LL;
			}
		}
		while (size() > 1 && dig.back() == 0) dig.pop_back();
	}
	BigInteger(ll a) {
		isNeg = a < 0;
		dig.pb(abs(a));
		if(dig.back() >= BASE) {
			ll tmp = dig.back() / BASE;
			dig.back() %= BASE;
			dig.pb(tmp);
		}
		while (size() > 1 && dig.back() == 0) dig.pop_back();
	}
	int size() const {return dig.size();}
	BigInteger getAbs()const {
		if (!isNeg) return *this;
		BigInteger ret = *this;
		ret.isNeg = false;
		return ret.normal();
	}
	BigInteger normal() const {
		BigInteger ret = this->getAbs();
		for (int i = 0; i + 1 < ret.size(); ++i) {
			while (ret.dig[i] >= BASE) ret.dig[i + 1] += ret.dig[i] / BASE, ret.dig[i] %= BASE;
		}
		if (ret.dig.back() >= BASE) {
			ll tmp = ret.dig.back() / BASE;
			ret.dig.back() %= BASE;
			ret.dig.push_back(tmp);
		}
		while (ret.size() > 1 && ret.dig.back() == 0) ret.dig.pop_back();
		return ret;
	}
	pair<BigInteger, ll> divMod(ll a) const {
		BigInteger x = *this;
		ll c = 0, t;
		for (int i = x.size() - 1; i >= 0; --i) {
			t = BASE * c + x.dig[i];
			x.dig[i] = t / a;
			c = t % a;
		}
		return pair<BigInteger, ll>(x.normal(), c);
	}
	pair<BigInteger, BigInteger> divMod(const BigInteger& bi) const {
		BigInteger x = this->getAbs(), y = bi.getAbs();
		if (x < y) return pair<BigInteger, BigInteger>(make_pair(BigInteger("0"), *this));
		if (x == y) return pair<BigInteger, BigInteger> (BigInteger("1"), BigInteger("0"));
		ll F = BASE / (y.dig.back() + 1);
		x = x * F;
		y = y * F;

		BigInteger z(0LL, x.size() - y.size() + 1, isNeg ^ bi.isNeg);
		for (int k = z.size() - 1, i = x.size() - 1; k >= 0; --k, --i) {
			z.dig[k] = (i + 1 < x.size() ? x.dig[i + 1] : 0) * BASE + x.dig[i];
			z.dig[k] /= y.dig.back();
			BigInteger t(0, k + y.size());
			for (int m = 0; m < y.size(); ++m) {
				t.dig[k + m] = z.dig[k] * y.dig[m];
			}

			t = t.normal();
			while (x < t) {
				z.dig[k] -= 1;
				for (int m = 0; m < y.size(); ++m) {
					t.dig[k + m] -= y.dig[m];
				}
				t = t.normal();
			}
			x = x - t;
		}
		return pair<BigInteger, BigInteger>(z.normal(), x / F);
	}
	BigInteger operator + (const BigInteger& bi) const {
		bool retNeg = false;
		if (isNeg) {
			if (bi.isNeg) retNeg = true;
			else bi - (this->getAbs());
		}
		if (bi.isNeg) return (*this) - bi.getAbs();
		BigInteger ret (0LL, max(this->size(), bi.size()) + 1, retNeg);
		for (int i = 0; i + 1 < ret.size(); ++i) {
			if (i < this->size()) ret.dig[i] += this->dig[i];
			if (i < bi.size()) ret.dig[i] += bi.dig[i];
			if (ret.dig[i] >= BASE) ret.dig[i] -= BASE, ++ret.dig[i + 1];
		}
		return ret.normal();
	}
	BigInteger operator - (const BigInteger& bi) const {
		if (bi.isNeg) return (*this) + bi.getAbs();
		if (isNeg) return bi - (this -> getAbs());
		if ((*this) < bi) {
			BigInteger ret = bi - (*this);
			ret.isNeg = true;
			return ret;
		}
		BigInteger ret = *this;
		for (int i = 0; i < bi.size(); ++i) {
			ret.dig[i] -= bi.dig[i];
			if (ret.dig[i] < 0) ret.dig[i] += BASE, --ret.dig[i+1];
		}
		return ret.normal();
	}
	BigInteger operator * (const ll a) const {
		BigInteger ret = *this;
		for (auto& d : ret.dig) d *= a;
		return ret.normal();
	}
	BigInteger operator * (const BigInteger& bi)  const {
		BigInteger ret(0LL, this->size() + bi.size(), isNeg ^ bi.isNeg);
		for (int i = 0; i < this->size(); ++i) {
			for (int j = 0; j < bi.size(); ++j) {
				ret.dig[i + j] += this->dig[i] * bi.dig[j];
			}
			for(int j = 0; j + 1< ret.size(); ++j) {
				if(ret.dig[j] >= BASE) {
					ret.dig[j+1] += ret.dig[j] / BASE;
					ret.dig[j] %= BASE;
				}
			}
			if(ret.dig.back() >= BASE) {
				ll tmp = ret.dig.back() / BASE;
				ret.dig.back() %= BASE;
				ret.dig.push_back(tmp);
			}
		}
		return ret.normal();
	}
	BigInteger operator / (ll a) const {return this->divMod(a).first;}
	ll operator % (ll a) const {return this->divMod(a).second;}
	BigInteger operator / (const BigInteger& bi) const {return this->divMod(bi).first;}
	BigInteger operator % (const BigInteger& bi) const {return this->divMod(bi).second;}
	bool operator < (const BigInteger& bi) const {
		if (this->size() != bi.size()) return this->size() < bi.size();
		for (int i = this->size() - 1; i >= 0; --i) {
			if (dig[i] != bi.dig[i]) return dig[i] < bi.dig[i];
		}
		return false;
	}
	bool operator > (const BigInteger& bi) const {return bi < (*this);}
	bool operator <= (const BigInteger& bi) const {!(*this > bi);}
	bool operator >= (const BigInteger& bi) const {!(*this < bi);}
	bool operator != (const BigInteger& bi) const {(*this < bi) || (*this > bi);}
	bool operator == (const BigInteger& bi) const {!(*this != bi);}
	void print() const{
		if(isNeg) printf("-");
		printf("%lld", dig.back());
		for(int i = size()-2; i>=0; --i) printf("%0*lld", LogBase, dig[i]);
	}
	void println() const {
		print();
		puts("");
	}
};
ostream &operator << (ostream &os, const BigInteger& x) {
	if (x.isNeg) os << '-';
	os << x.dig[x.size() - 1];
	for (int i = x.size() - 2; i >= 0; --i) {
		os << setw(BigInteger::LogBase) << setfill('0') << x.dig[i];
	}
	return os;
}
istream &operator >> (istream &is, BigInteger &x) {
	string s; is >> s; x = BigInteger(s); return is;
}


int main() {
	ll n, m, r;
	cin >> n >> m >> r;
	BigInteger b = BigInteger("1");
	int R = r - n * m;
	if(R < 0) {
		cout << 0 << endl;
		return 0;
	}
	for(int i = 0; i < n-1; ++i) {
		b = b * BigInteger(R+n-1-i);
		b = b /BigInteger(i+1);
	}
	cout << b << endl;
	return 0;
}

Measured memory_bytes: 3248