import sys


def input(): return sys.stdin.readline().rstrip()


def main():
    N, M, K = map(int, input().split())
    D = [[K+1]*N for i in range(N)]
    for i in range(N):
        D[i][i] = 0

    for i in range(M):
        u, v = map(int, input().split())
        D[u-1][v-1] = D[v-1][u-1] = 1

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

    def TSP(A):
        D = [[K+1]*(len(A)-1) for i in range(1 << (len(A)-1))]
        for i in range(len(A)-1):
            D[1 << i][i] = A[0][i+1]
        for i in range(1 << (len(A)-1)):
            for j in range(len(A)-1):
                if i & (1 << j):
                    for k in range(len(A)-1):
                        D[i][j] = min(D[i][j], D[i-(1 << j)][k] + A[j+1][k+1])
        return min(D[-1])

    def ok(arr):
        return TSP([[D[i][j] for i in arr] for j in arr]) <= K

    ret = [0]
    for i in range(N-1, 0, -1):
        if ok(ret + [i]):
            ret.append(i)
        if len(ret) == K+1:
            break

    print(sum(map(lambda x: 2**x-1, ret)))


if __name__ == '__main__':
    main()