import sys
input = sys.stdin.readline

N,M,K=list(map(int,input().split()))
E=[[] for i in range(N)]
E_INV=[[] for i in range(N)]

for i in range(M):
    a,b=list(map(int,input().split()))
    a-=1
    b-=1
    E[a].append(b)
    E_INV[b].append(a)

LIST=[]
OTHER=[]
for i in range(N):
    if len(E[i])>0:
        LIST.append(i)
    else:
        OTHER.append((len(E_INV[i]),i))


if len(LIST)>=K+1:
    score=0
    for x in LIST:
        score+=K-len(E_INV[x])

    print(score)
else:
    OTHER.sort(reverse=True)

    for i in range(len(OTHER)):
        if len(LIST)>=K+1:
            break
        LIST.append(OTHER[i][1])

    score=0
    for x in LIST:
        score+=K-len(E_INV[x])

    print(score)