import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

# https://judge.yosupo.jp/submission/216433
# https://qiita.com/AkariLuminous/items/a2c789cebdd098dcb503
# O(N + M)
class SCC:
    def __init__(self, n):
        self.n = n
        self.edges = []
        self.start = [0] * (n + 1)
        self.mask = (1 << 31) - 1
        self.shift = 31

    def add_edge(self, a, b):
        self.edges.append((a << self.shift) + b)
        self.start[a + 1] += 1

    def csr(self):
        for i in range(self.n):
            self.start[i + 1] += self.start[i]
        counter = self.start[:]
        self.elist = [0] * len(self.edges)
        for ab in self.edges:
            a, b = ab >> self.shift, ab & self.mask
            self.elist[counter[a]] = b
            counter[a] += 1

    def scc(self):
        self.csr()
        n = self.n
        now_ord = group_num = 0 # 探索した頂点数、見つかったSCCの個数
        visited = [] # まだ確定していない頂点のリスト
        low = [0] * n # lowlink
        order = [-1] * n # order
        ids = [0] * n # scc_id
        parent = [-1] * n
        stack = []
        groups = [] # 各SCCの頂点リスト
        for i in range(n):
            if order[i] != -1:
                continue
            stack.append(i)
            stack.append(i)
            while stack:
                v = stack.pop()
                if order[v] == -1: # 1回目の訪問
                    low[v] = order[v] = now_ord
                    now_ord += 1
                    visited.append(v)
                    for k in range(self.start[v], self.start[v + 1]):
                        to = self.elist[k]
                        if order[to] == -1:
                            stack.append(to)
                            stack.append(to)
                            parent[to] = v
                        else:
                            low[v] = min(low[v], order[to])
                else: # 2回目の訪問
                    if low[v] == order[v]: # 根ならSCCが確定
                        group = []
                        while True:
                            u = visited.pop()
                            order[u] = n # 確定済み
                            ids[u] = group_num
                            group.append(u)
                            if u == v:
                                break
                        groups.append(group)
                        group_num += 1
                    if parent[v] != -1:
                        low[parent[v]] = min(low[parent[v]], low[v])
        for i, x in enumerate(ids):
            ids[i] = group_num - 1 - x
        return group_num, ids, groups[::-1]

def check(x):
    if x == 0:
        return False
    while x % 2 == 0:
        x //= 2

    while x % 5 == 0:
        x //= 5
    return x == 1

from math import gcd
def solve():
    n, m, k = na()
    scc = SCC(n)
    g = [[] for i in range(n)]
    for _ in range(m):
        a, b = na()
        a -= 1
        b -= 1
        g[a].append(b)
        scc.add_edge(a, b)
    _, _, res = scc.scc()
    

    a = [0] * n
    for t in range(len(res)):
        for i in res[t]:
            a[i] = t    

    dist = [-1] * n
    q = []
    f = [0] * len(res)
    for i in range(n):
        if f[a[i]] == 0:
            f[a[i]] = 1
            q.append(i)
            dist[i] = 0
    
    while q:
        x = q.pop()
        for y in g[x]:
            if dist[y] == -1 and a[x] == a[y]:
                dist[y] = dist[x] + 1
                q.append(y)

    ans = [0] * len(res)
    for i in range(n):
        for j in g[i]:
            if a[i] == a[j]:
                ans[a[i]] = gcd(ans[a[i]], dist[j] - dist[i] - 1)
    # print(ans)

    ok = [0] * (len(res) - 1)
    for i in range(n):
        for j in g[i]:
            if a[j] == a[i] + 1:
                ok[a[i]] = 1
    
    if 0 in res[0] and all(x == 1 for x in ok) and all(x == 0 or x % 2 == 1 for x in ans) and all(ans[i] != 0 or ans[i+1] != 0 for i in range(len(ans) - 1)) and ans[0] != 0:
        Yes()
    else:
        No()
    
    

solve()