// clang-format off
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <bitset>
#include <vector>
#include <algorithm>
#include <random>
#include <map>
#include <string>
#include <set>
#include <deque>
#include <string>
#include <cassert>

#pragma GCC optimize("Ofast")

using namespace std;
const int N = 1e6 + 7, MOD = 998244353, M = 139;
const long double EPS = 1e-10, PI = acos(-1);

using ll = long long;

ll binpow(ll a, int step) {
    if (step == 0) {
        return 1;
    }
    ll h = binpow(a, step / 2);
    h = (h * h) % MOD;
    if (step % 2) {
        h = (h * a) % MOD;
    }
    return h;
}

ll pows[N];
ll q = 149;

struct Hash {
    ll hsh = 0;
    int len;
    void pop_back(int a) {
        hsh -= ((a + 1) * pows[len - 1]) % MOD;
        if (hsh < 0) {
            hsh += MOD;
        }
        len--;
    }
    void push_front(int a) {
        hsh *= q;
        hsh += a + 1;
        hsh %= MOD;
        len++;
    }
};

Hash fwd[N], fwd2[N];

int a[N], b[N], n, m, q1, bwd[N];


int z[N];

vector<int> s;

bool good[N];

void zfun() {
    int n = s.size();
    z[0] = 0;
    int L = 0, R = 0;
    for (int i = 1; i < n; i++) {
        z[i] = max(0, min(z[i - L], R - i+1));
        while (i + z[i] < n && s[i + z[i]] == s[z[i]]) {
            z[i]++;
        }
        if (i + z[i] - 1 > R) {
            L = i;
            R = i + z[i] - 1;
        }
    }
}

signed main() {
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
#else
    std::ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    pows[0] = 1;
    for (int i = 1; i < N; i++) {
        pows[i] = (q * pows[i - 1]) % MOD;
    }
    cin >> n >> m >> q1;
    for (int i = 0; i < m; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
        cin >> b[i];
    }
    for (int i = m - 1; i >= 0; i--) {
        if (i + q1 >= m) {
        }
        else {
            fwd[i] = fwd[i + q1];
            fwd[i].push_front((a[i] - a[i + q1] + M) % M);
        }
    }
    for (int i = n - 1; i >= 0; i--) {
        if (i + q1 >= n) {
        }
        else {
            fwd2[i] = fwd2[i + q1];
            fwd2[i].push_front((b[i] - b[i+q1] + M) % M);
            if (fwd2[i].len >= m / q1) {
                int i1 = i + q1 * (fwd2[i].len - 1);
                fwd2[i].pop_back((b[i1] - b[i1 + q1] + M) % M);
            }
        }
    }
    s.clear();
    for (int i = 0; i < q1; i++) {
        s.push_back(fwd[i].hsh);
    }
    int ln = s.size() + 1;
    s.push_back(-1);
    for (int i = 0; i < n; i++) {
        s.push_back(fwd2[i].hsh);
    }
    zfun();
    for (int i = ln; i < s.size(); i++) {
        if (z[i] >= q1) {
            good[i - ln] = 1;
            //cout << i - ln << " ";
        }
    }
    s.clear();
    for (int i = 0; i < q1; i++) {
        s.push_back(a[i]);
    }
    s.push_back(-1);
    for (int i = 0; i < n; i++) {
        if (i - q1 >= 0) {
            s.push_back((b[i] - b[i - q1] + M) % M);
        }
        else {
            s.push_back(-1);
        }
    }
    zfun();
    for (int i = ln; i < s.size(); i++) {
        if (z[i] >= q1) {
            good[i - ln] &= 1;
        }
        else {
            good[i - ln] = 0;
        }
    }
    for (int i = q1; i < n; i++) {
        if (good[i]) {
            cout << i - q1 + 1;
            return 0;
        }
    }
    cout << -1;
}