#include <bits/stdc++.h>
using namespace std;
#define FOR(i,k,n) for(int i = (int)(k); i < (int)(n); i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) a.begin(), a.end()
#define MS(m,v) memset(m,v,sizeof(m))
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> pii;
const int MOD = 1000000007;
const int INF = MOD + 1;
const ld EPS = 1e-12;
template<class T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<class T> T &chmax(T &a, const T &b) { return a = max(a, b); }

/*--------------------template--------------------*/


typedef ll Data;
typedef vector<Data> Array;
typedef vector<Array> Matrix;

bool is_zero(Data dat) { return (abs(dat) < EPS); }

Matrix operator-(Matrix mat) {
	REP(i, mat.size()) REP(j, mat[0].size()) mat[i][j] = -mat[i][j];
	return mat;
}

Matrix operator+(Matrix lhs, const Matrix &rhs) {
	REP(i, lhs.size()) REP(j, lhs[0].size()) lhs[i][j] = lhs[i][j] + rhs[i][j];
	return lhs;
}

Matrix operator-(Matrix lhs, const Matrix &rhs) {
	REP(i, lhs.size()) REP(j, lhs[0].size()) lhs[i][j] = lhs[i][j] - rhs[i][j];
	return lhs;
}

Matrix operator*(const Matrix &lhs, const Matrix &rhs) {
	Matrix res(lhs.size(), Array(rhs[0].size(), 0));
	REP(i, lhs.size()) REP(j, rhs[0].size()) REP(k, rhs.size())
		res[i][j] = fma(lhs[i][k], rhs[k][j], res[i][j]);
	return res;
}

Array operator+(const Array &lhs, const Array &rhs) {
	Array res = lhs;
	REP(i, rhs.size()) res[i] = res[i] + rhs[i];
	return res;
}

Array operator*(const Matrix &lhs, const Array &rhs) {
	Array res(lhs.size());
	REP(i, lhs.size())
		res[i] = inner_product(begin(lhs[i]), end(lhs[i]), begin(rhs), Data(0));
	return res;
}

Array operator*(Data scalar, const Array &rhs) {
	Array res(rhs.size());
	REP(i, rhs.size())
		res[i] = scalar * rhs[i];
	return res;
}

Matrix transpose(const Matrix &A) {
	const ll n = A[0].size(), m = A.size();
	Matrix res(n, Array(m, 0));
	REP(i, n)REP(j, m) res[i][j] = A[j][i];
	return res;
}

Data inner_product_ex(const Array& a, const Array& b, const Matrix& m) {
	Array b_prime = m*b;
	return inner_product(begin(a), end(a), begin(b_prime), Data(0));
}

Data norm(const Array &a) {
	return inner_product(begin(a), end(a), begin(a), Data(0));
}

Data norm(const Array &a, const Matrix &M) {
	return inner_product_ex(a, a, M);
}

ll rankMat(Matrix A) {
	const ll n = A.size(), m = A[0].size();
	ll r = 0;
	for (ll i = 0; r < n && i < m; ++i) {
		ll pivot = r;
		for (ll j = r + 1; j < n; ++j)
			if (abs(A[j][i]) > abs(A[pivot][i])) pivot = j;
		swap(A[pivot], A[r]);
		if (is_zero(A[r][i])) continue;
		for (ll k = m - 1; k >= i; --k)
			A[r][k] = A[r][k] / A[r][i];
		for (ll j = r + 1; j < n; ++j)
			for (ll k = m - 1; k >= i; --k)
				A[j][k] = fma(-A[r][k], A[j][i], A[j][k]);
		++r;
	}
	return r;
}

Data det(Matrix A) {
	const ll n = A.size();
	Data D = Data(1);
	for (ll i = 0; i < n; ++i) {
		ll pivot = i;
		for (ll j = i + 1; j < n; ++j)
			if (abs(A[j][i]) > abs(A[pivot][i])) pivot = j;
		swap(A[pivot], A[i]);
		D = D * A[i][i] * Data(i != pivot ? -1 : 1);
		if (is_zero(A[i][i])) break;
		for (ll j = i + 1; j < n; ++j)
			for (ll k = n - 1; k >= i; --k)
				A[j][k] = A[j][k] - A[i][k] * A[j][i] / A[i][i];
	}
	return D;
}

Matrix pow(Matrix x, ll n)
{
	ll sz = x.size();
	Matrix res(sz, Array(sz));
	REP(i, sz) res[i][i] = 1;
	while (n > 0)
	{
		if (n & 1) res = res * x;
		x = x*x;
		n >>= 1;
	}
	return res;
}


void output(bool f)
{
	cout << (f ? "yes" : "no") << endl;
}

ll n, m, z;
map<pii, ll> mp;

int main()
{
	cin.sync_with_stdio(false); cout << fixed << setprecision(10);
	while (cin >> n >> m >> z, n)
	{
		mp.clear();
		vector<vi> node(n);
		REP(i, m)
		{
			ll a, b; cin >> a >> b;
			a--; b--;
			if (b == 0) swap(a, b);
			mp[pii(b, a)] = 1 + i * 2;
			node[a].push_back(1 + i * 2);
			mp[pii(a, b)] = 2 + i * 2;
			node[b].push_back(2 + i * 2);
		}
		ll nn = mp.size() + 1;
		Matrix mat(nn, Array(nn));
		for (auto e : mp)
		{
			ll from = e.first.first, to = e.first.second;
			if (from == 0)
			{
				mat[0][mp[pii(from, to)]] = 1;
			}
			for (auto i : node[from])
			{
				if (i == mp[pii(to, from)]) continue;
				mat[i][mp[pii(from, to)]] = 1;
			}
		}
		Matrix ans(1, Array(nn));
		ans[0][0] = 1;
		ans = ans * pow(mat, z);
		bool f = false;
		for (auto i : node[n - 1])
		{
			if (ans[0][i]) f = true;
		}
		output(f);
	}
	return 0;
}

Measured memory_bytes: 3316