#include<bits/stdc++.h>

using namespace std;

const int N = 105;
int n, f, t;
set<int> s;

int main() {
    scanf("%d %d %d", &n, &f, &t);
    vector<int> a(n);
    for (auto &e: a) scanf("%d", &e);
    vector<int> ca = a;
    sort(ca.rbegin(), ca.rend());
    int csum = 0;
    for (int i = 0; i < f; i++) csum += ca[i];
    if (csum < t) printf("NO"), exit(0);
    for (int i = f; i < n; i++) if (a[i]) s.emplace(i);
    int cur = 0, ans = 0;
    for (int i = 0; i < f; i++) cur += a[i];
    for (int i = f - 1; i >= 0; i--) {
        if (!a[i]) {
            cur += (a[i] = 1);
            ans += *s.begin() - i;
            s.erase(s.begin());
        }
        if (cur >= t) break;
    }
    printf("%d", ans);
}