#include <bits/stdc++.h>

using i16 = std::int16_t;
using i32 = std::int32_t;
using i64 = std::int64_t;
using usize = std::size_t;
using namespace std;

#define rep(i, max) for(i32 i = 0; i < (i32)max; ++i)
#define loop while(true)
#define allOf(collection) collection.begin(), collection.end()

unique_ptr<string> readLine() { unique_ptr<string> line(new string()); getline(cin, *line); return line; }
template<typename T1, typename T2> pair<T1, T2> readPair() { T1 res1; cin >> res1; T2 res2; cin >> res2; readLine(); return make_pair(res1, res2);}
template<typename T> unique_ptr<vector<T>> readVector(usize num, bool isForIndex = false) { unique_ptr<vector<T>> list(new vector<T>(num)); rep(i, num) { cin >> (*list)[i]; if(isForIndex) --(*list)[i]; } readLine(); return list; }
void readValues() { readLine(); }
template<typename H, typename... T> void readValues(H& head, T&&... tails){ H a; cin >> a; head = a; readValues(forward<T>(tails)...); }
void writeLine() { cout << endl; }
template<typename T> void write(const T& arg) { cout << arg; }
template<typename T> void writeLine(const vector<T>& arg){ if(arg.empty()) { writeLine(); return; } write(arg[0]); for(int i = 1; i < arg.size(); ++i){ write(" "); write(arg[i]); } writeLine(); }
template<typename T> void writeLine(const T& arg) { cout << arg << endl; }
void recursiveCombination(vector<i32>& indexes, i32 s, i32 rest, function<void(vector<i32>&)> f) { if (rest == 0) { f(indexes); } else { if (s < 0) return; recursiveCombination(indexes, s - 1, rest, f); indexes[rest - 1] = s; recursiveCombination(indexes, s - 1, rest - 1, f); } }
void foreachWithCombination(i32 n, i32 k, function<void(vector<i32>&)> f) { auto indexes = vector<i32>(k); recursiveCombination(indexes, n - 1, k, f); }
void foreachWithPermutaton(i32 n, function<void(vector<i32>&)> f) { auto indexes = vector<i32>(); indexes.reserve(n); rep(i, (usize)n) indexes.push_back(i); do f(indexes); while (next_permutation(allOf(indexes))); }
void foreachWithPermutaton(i32 n, i32 k, function<void(vector<i32>&)> f){ foreachWithCombination(n, k, [=](vector<i32>& combIndexes){ foreachWithPermutaton(k, [=](vector<i32>& permIndexes){ auto indexes = vector<i32>(); indexes.reserve(k); rep(i, (usize)k){ indexes.push_back(combIndexes[permIndexes[i]]); } f(indexes); }); }); }
void program();
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    program();
}

void program() {
    i32 n, k;
    readValues(n, k);
    auto p = *readVector<i32>(n, true);
    auto c = *readVector<i32>(n);
    i64 scoreMaxi = INT64_MIN;

    rep(i, n) {
        i64 cycleSum = 0;
        i32 indexCount = 0;
        i32 s = i;
        loop {
            ++indexCount;
            cycleSum += c[s];
            s = p[s];
            if(s == i) break;
        }

        i64 rest = 0;
        i64 count = 0;
        
        loop {
            ++count;
            rest += c[s];

            if(count > k) break;
            int num = (k - count) / indexCount;
            i64 score = rest + max((i64)0, cycleSum) * num;
            scoreMaxi = max(scoreMaxi, score);
            s = p[s];
            if (s == i) break;
        }
    }
    writeLine(scoreMaxi);
}

Measured memory_bytes: 3588