#include <bits/stdc++.h>
using namespace std;

#define int long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define reps(i, n) for (int i = 1; i <= (n); i++)
#define all(x) (x).begin(), (x).end()
#define uniq(x) (x).erase(unique(all(x)), end(x))
#define bit(n) (1LL << (n))
#define cdiv(a, b) (((a) - 1) / (b) + 1)
#define dump(x) cerr << #x " = " << (x) << endl
using vint = vector<int>;
using vvint = vector<vint>;
using pint = pair<int, int>;
using vpint = vector<pint>;
template<typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
constexpr double PI = 3.1415926535897932384626433832795028;
constexpr int DY[8] = {0, 1, 0, -1, 1, 1, -1, -1};
constexpr int DX[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int gcd(int a, int b) {
    while (b) { swap(a %= b, b); }
    return a;
}
int lcm(int a, int b) { return a / gcd(a, b) * b; }
template<typename T> void fin(T mes) {
    cout << mes << endl;
    exit(0);
}
template<typename T, typename U> bool chmax(T &a, const U &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template<typename T, typename U> bool chmin(T &a, const U &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template<typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &rhs) {
    os << "(" << rhs.first << ", " << rhs.second << ")";
    return os;
}
template<typename T> ostream &operator<<(ostream &os, const vector<T> &rhs) {
    os << "{";
    for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
        os << *itr << (next(itr) != rhs.end() ? ", " : "");
    }
    os << "}";
    return os;
}
struct setup {
    static constexpr int PREC = 20;
    setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} setup;

/*
 * Koch Curve http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_5_C
 * 約10分
 * 実装例があったので頭がバグらずに済みました。複素数を使うと楽だと思います。
 */

template<typename M>
struct matrix {
    using T = typename M::T;
    int h, w;
    std::vector<std::vector<T>> data;
    matrix(int h, int w) : h(h), w(w), data(h, std::vector<T>(w, M::id_pl())) {}
    matrix(const std::vector<std::vector<T>> &src) : h(src.size()), w(src[0].size()), data(src) {}
    std::vector<T> &operator[](int i) { return data[i]; }
    const std::vector<T> &operator[](int i) const { return data[i]; }
    static matrix identity(int n) {
        matrix ret(n, n);
        for (int i = 0; i < n; i++) { ret[i][i] = M::id_cr(); }
        return ret;
    }
    bool operator==(const matrix &rhs) const {
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                if (data[i][j] != rhs[i][j]) { return false; }
            }
        }
        return true;
    }
    bool operator!=(const matrix &rhs) const { return std::rel_ops::operator!=(*this, rhs); }
    matrix &operator+=(const matrix &rhs) {
        assert(h == rhs.h && w == rhs.w);
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                (*this)[i][j] = M::pl((*this)[i][j], rhs[i][j]);
            }
        }
        return *this;
    }
    matrix &operator-=(const matrix &rhs) {
        assert(h == rhs.h && w == rhs.w);
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                (*this)[i][j] = M::pl((*this)[i][j], M::inv_pl(rhs[i][j]));
            }
        }
        return *this;
    }
    matrix &operator*=(const matrix &rhs) {
        assert(w == rhs.h);
        std::vector<std::vector<T>> ret(h, std::vector<T>(rhs.w, M::id_pl()));
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < rhs.w; j++) {
                for (int k = 0; k < w; k++) {
                    ret[i][j] = M::pl(ret[i][j], M::cr((*this)[i][k], rhs[k][j]));
                }
            }
        }
        data = ret;
        h = data.size(), w = data[0].size();
        return *this;
    }
    matrix &operator/=(const matrix &rhs) { return *this *= rhs.inv(); }
    matrix operator+() const { return *this; }
    matrix operator-() const { return matrix(h, w) -= (*this); }
    matrix operator+(const matrix &rhs) const { return matrix(*this) += rhs; }
    matrix operator-(const matrix &rhs) const { return matrix(*this) -= rhs; }
    matrix operator*(const matrix &rhs) const { return matrix(*this) *= rhs; }
    matrix operator/(const matrix &rhs) const { return matrix(*this) /= rhs; }
    matrix inv() const {
        assert(h == w);
        matrix id = identity(h);
        std::vector<std::vector<T>> ex(h, std::vector<T>(w << 1));
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) { ex[i][j] = (*this)[i][j]; }
            for (int j = 0; j < w; j++) { ex[i][w + j] = id[i][j]; }
        }
        for (int i = 0; i < h; i++) {
            for (int j = i; j < w; j++) {
                if (!M::is_id_pl(ex[i][j])) {
                    swap(ex[i], ex[j]);
                    break;
                }
            }
            if (M::is_id_pl(ex[i][i])) { return matrix(0, 0); }
            T inv = M::inv_cr(ex[i][i]);
            for (int j = i + 1; j < w << 1; j++) { ex[i][j] = M::cr(ex[i][j], inv); }
            for (int j = i + 1; j < h; j++) {
                for (int k = i + 1; k < w << 1; k++) {
                    ex[j][k] = M::pl(ex[j][k], M::inv_pl(M::cr(ex[i][k], ex[j][i])));
                }
            }
        }
        for (int i = h - 1; i > 0; i--) {
            for (int j = i - 1; j >= 0; j--) {
                for (int k = w; k < w << 1; k++) {
                    ex[j][k] = M::pl(ex[j][k], M::inv_pl(M::cr(ex[i][k], ex[j][i])));
                }
            }
        }
        std::vector<std::vector<T>> ret(h, std::vector<T>(w));
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                ret[i][j] = ex[i][w + j];
            }
        }
        return ret;
    }
    matrix pow(long long n) const {
        assert(h == w);
        matrix ret = identity(h), mul = *this;
        while (n > 0) {
            if (n & 1) { ret *= mul; }
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }
    friend std::ostream &operator<<(std::ostream &os, const matrix &rhs) {
        for (int i = 0; i < rhs.h; i++) {
            os << "[";
            for (int j = 0; j < rhs.w; j++) {
                os << rhs[i][j] << (j + 1 == rhs.w ? "]\n" : ",");
            }
        }
        return os;
    }
};

struct bool_mat {
    using T = bool;
    static T pl(const T &a, const T &b) { return a | b; }
    static T cr(const T &a, const T &b) { return a & b; }
    static T id_pl() { return 0; }
    static T id_cr() { return 1; }
    static T inv_pl(const T &a) { return 0; } // 本当はない
    static T inv_cr(const T &a) { return 0; } // 本当はない
    static bool is_id_pl(const T &a) { return a == 0; };
};

// Can I go there? 実装中
// 辺ベースでbool値の行列累乗をすればいけるはず

void solve(int N, int M, int Z) {
    vint s(M), d(M);
    vvint edx(N);
    vint rev(2 * M), to(2 * M);
    rep(i, M) {
        cin >> s[i] >> d[i];
        s[i]--, d[i]--;
        edx[s[i]].push_back(2 * i + 0), rev[2 * i + 0] = 2 * i + 1, to[2 * i + 0] = d[i];
        edx[d[i]].push_back(2 * i + 1), rev[2 * i + 1] = 2 * i + 0, to[2 * i + 1] = s[i];
    }
    matrix<bool_mat> a(M * 2 + 1, M * 2 + 1), b(M * 2 + 1, 1);
    b[M * 2][0] = 1;
    rep(i, edx[0].size()) { a[edx[0][i]][M * 2] = 1; }
    rep(i, M * 2) {
        int t = to[i];
        rep(j, edx[t].size()) { a[edx[t][j]][i] = 1; }
        a[rev[i]][i] = 0;
    }
    b = a.pow(Z) * b;
    bool ans = false;
    rep(i, M * 2) {
        if (to[i] == N - 1 && b[i][0]) { ans = true; }
    }
    if (ans) { cout << "yes" << endl; }
    else { cout << "no" << endl; }
}
signed main() {
    while (true) {
        int N, M, Z;
        cin >> N >> M >> Z;
        if (N == 0 && M == 0 && Z == 0) { break; }
        solve(N, M, Z);
    }
}
