import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)
inf = 10**9

N, M, K = map(int, input().split())
G = [[inf]*N for _ in range(N)]

for i in range(N):
    G[i][i] = 0
for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    G[a][b] = 1
    G[b][a] = 1

for k in range(N):
    for i in range(N):
        for j in range(N):
            if G[i][k] < inf and G[k][j] < inf:
                G[i][j] = min(G[i][j], G[i][k] + G[k][j])

node = [0]
for p in reversed(range(1, N)):
    if len(node) > K:
        break
    node.append(p)
    sz = len(node)
    dp = [[inf]*sz for _ in range(1 << sz)]  # mask:visited nodes, i:present
    dp[1][0] = 0
    for bit in range(1, (1 << sz)-1):
        for i, s in enumerate(node):
            if (bit >> i) & 1:
                for j, t in enumerate(node):
                    if i != j and ~(bit >> j) & 1:
                        nxt_bit = bit | (1 << j)
                        dp[nxt_bit][j] = min(dp[nxt_bit][j], dp[bit][i] + G[s][t])
    if all(dp[(1 << sz)-1][i] > K for i in range(sz)):
        node.pop()

ans = sum((1 << i)-1 for i in node)
print(ans)