if __name__ == "__main__":
    n, m, k = map(int, input().split())
    in_degree = [0 for _ in range(n)]
    out_degree = [0 for _ in range(n)]
    for i in range(m):
        a, b = map(int, input().split())
        a -= 1
        b -= 1
        in_degree[b] += 1
        out_degree[a] += 1

    requre_indices = [False for _ in range(n)]
    count = 0
    for i in range(n):
        if out_degree[i] > 0:
            requre_indices[i] = True
            count += 1

    indices = []
    for i in range(n):
        if out_degree[i] == 0:
            indices.append(i)
    indices.sort(key=lambda i: -in_degree[i])
    
    if count < k + 1:
        for i in range(k + 1 - count):
            requre_indices[indices[i]] = True

    ans = 0
    for i in range(n):
        if requre_indices[i]:
            ans += (k - in_degree[i])

    print(ans)