LL calc(int M) {
memset(ok, false, sizeof ok);
for (int j = 0; j < n; ++j)
if (g[j].second <= M)
ok[j] = true;
LL ret = 0;
mf.init();
mf.s = n + m + 1;
mf.t = n + m + 2;
for (int j = 0; j < m; ++j) {
bool flg = true;
for (int k = 0; k < (int)f[j].size(); ++k)
if (!ok[f[j][k]]) {
flg = false;
break;
}
if (flg) {
ret += pro[j];
mf.addEdge(mf.s, j, pro[j]);
for (int k = 0; k < (int)f[j].size(); ++k)
mf.addEdge(j, m + f[j][k], INF);
}
}
for (int j = m; j < n + m; ++j)
if (ok[j-m])
mf.addEdge(j, mf.t, g[j-m].first);
return ret - mf.maxFlow();
}
bool check(double lamda) {
double ans;
for(int i = 0; i < M; ++i) {
mf.buf[i].c -= lamda;
if(mf.buf[i].c < 0) ans += mf.buf[i].c;
}
ans += mf.maxFlow(1, N);
for(int i = 0; i < M; ++i)
mf.buf[i].c += lamda;
return ans < 0;
}
int main() {
while( scanf( "%d%d%d%d", &N, &S, &T, &M ) != EOF ) {
build();
printf( "%d\n", mf.maxFlow( N, N + 1 ) );
}
}
int main() {
while( cin >> N >> S >> T >> M ) {
build();
cout << mf.maxFlow( N, N + 1 )<< endl;
}
}
bool check( int flow ) {
for( int i = st; i < ed; ++i )
mf.buf[i].c = flow;
return mf.maxFlow( 0, N + M + 1 ) == N;
}