import sequtils,strutils,math
var
    N,M,K,u,v : int
    D : array[1..60, array[1..60, int]]
(N, M, K) = stdin.readline.split.map(parseInt)

for i in 1..N:
    for j in 1..N:
        D[i][j] = 200

for m in 1..M:
    (u,v) = stdin.readline.split.map(parseInt)
    D[u][v] = 1
    D[v][u] = 1

for k in 1..N:
    for i in 1..N:
        for j in 1..N:
            D[i][j] = min(D[i][j], D[i][k] + D[k][j])

var
    p : int
    tezyun = newSeqWith(1, 1)
    x : int
    DP : array[(1 shl 20) + 1,array[17,int]]

for n in countdown(N, 1):
    if D[1][n] > K:
        continue
    tezyun.add(n)
    for i in 1..(1 shl tezyun.high):
        for j in 0..tezyun.high:
            DP[i * 2 - 1][j] = 10000
    DP[1][0] = 0
    var k = 1
    while k < (1 shl tezyun.len):
        for p in 0..tezyun.high:
            if DP[k][p] > K:
                continue
            for t in 1..tezyun.high:
                if (k and (1 shl t)) == 0:
                    DP[k + (1 shl t)][t] = min(DP[k + (1 shl t)][t], DP[k][p] + D[tezyun[t]][tezyun[p]])
        k += 2
                    
    var flag = false
    for p in 1..tezyun.high:
        if DP[(1 shl tezyun.len) - 1][p] <= K:
            flag = true
            break
    if not flag:
        discard tezyun.pop()

var ans : int64
for t in tezyun:
    ans += (1.int64 shl (t - 1)) - 1
echo ans