#include <algorithm>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define inf 1000000000
#define MAXN 100000
#define swap(a,b) a^=b; b^=a; a^=b;

using namespace std;

struct state {
    vector<int> a;
    int nr_moves;
    state *previous;
    int i, j;
    state(int _nr_moves, vector<int> _a, int _i = 0, int _j = 0) {
        nr_moves = _nr_moves; a = _a; i = _i; j = _j;
    }
};

int maxes[100];
int n;

void print(state *s) {
    int br = 0;
    while (s != NULL && br++ < 3) {
        s = s->previous;
        printf("s.nr_moves:%d s->i:%d s->j:%d\n", s->nr_moves, s->i, s->j);
    }
}

int main() {
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        scanf("%d", &maxes[i]);
    }
    maxes[n] = INT_MAX;

    int where;
    scanf("%d", &where);
    for (int i = 0; i < n; ++i) {
        if (maxes[i] == where) {
            where = i;
            break;
        }
    }
    int cap;
    scanf("%d", &cap);

    vector<int> a = vector<int>(n, 0);
    a.push_back(inf);
    ++n;

    queue<state> kju;
    kju.push(state(0, a));
    set<string> bio;
    while (!kju.empty()) {
        state s = kju.front(); kju.pop();

        if (s.a[where] == cap) {
            print(&s);
            // printf("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n");
            return 0;
        }

        string key = "";
        char st[10];
        for (int i = 0; i < n-1; ++i) {
            sprintf(st, "%5d#", s.a[i]);
            key += string(st);
        }
        printf("key:%s\n", key.c_str());
        if (bio.find(key) != bio.end()) continue;
        bio.insert(key);

        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (i == j) continue;
                printf("i:%d j:%d\n", i, j);

                // from i to j
                if (s.a[i] != 0 && s.a[j] != maxes[j]) {
                    printf("ubacujemo vodu!\n");
                    int litres = min(s.a[i], maxes[j] - s.a[j]);
                    a = s.a;
                    a[i] -= litres;
                    a[j] += litres;
                    if (i < n-1) {
                        sprintf(st, "%5d#", a[i]);
                        key.replace(i*6, 6, string(st));
                    }
                    if (j < n-1) {
                        sprintf(st, "%5d#", a[j]);
                        key.replace(j*6, 6, string(st));
                    }
                    printf("key:%s\n", key.c_str());

                    if (bio.find(key) == bio.end()) {
                        state *new_state = new state(s.nr_moves+1, a, i, j);
                        new_state->previous = &s;
                        kju.push(*new_state);
                    }

                    if (i < n-1) {
                        sprintf(st, "%5d#", s.a[i]);
                        key.replace(i*6, 6, string(st));
                    }
                    if (j < n-1) {
                        sprintf(st, "%5d#", s.a[j]);
                        key.replace(j*6, 6, string(st));
                    }
                    printf("key:%s\n", key.c_str());
                }
            }
        }
    }

    return 0;
}