D

#include <iostream>

using namespace std;

const int N = 2000000, mod = 1000000007;

int cnt[2], target;
long long fact[N];

#define forn(i,n) for(int i = 0; i < (int) n; i++)
#define sz(a) (int)(a).size()

inline bool read() {
	return (cin >> cnt[0] >> cnt[1] >> target);
}

inline long long bpow(long long v, int power) {
	if (power == 0) return 1;
	if ((power & 1) == 0) {
		long long r = bpow(v, power >> 1);
		return (r * r) % mod;
	}
	return (bpow(v, power - 1) * v) % mod;
}

inline int getC(int n, int k) {
	long long nom = fact[n];
	long long den = (fact[n-k] * fact[k]) % mod;
	return (nom * bpow(den, mod - 2)) % mod;
}

int calculate() {
	if (cnt[1] == 0) {
		if (cnt[0] % 2 != target)
			return 1;
		else
			return 0;
	}
	if (cnt[0] == 0) {
		if (cnt[1] > 1) {
			if (target == 0)
				return 1;
			else
				return 0;
		} else {
			if (target == 1)
				return 1;
			else
				return 0;
		}
	}
	int answer = 0;
	for(int i = 0; i <= cnt[0]; i++) {
		int total = cnt[0] + cnt[1] - 1 - i;
		if (total > 0) {
			if (i % 2 == target) {
				answer += getC(total, cnt[1] - 1);
				if (answer >= mod) answer -= mod;
			}
		} else {
			if (i % 2 != target) {
				answer += getC(total, cnt[1] - 1);
				if (answer >= mod) answer -= mod;
			}
		}
	}
	return answer;
}

inline void solve() {
	fact[0] = 1;
	forn(i, N) {
		if (!i) continue;
		fact[i] = (fact[i-1] * i) % mod;
	}
	cout << calculate() << endl;
}
int main() {
	while (read())
		solve();
}