#include <bits/stdc++.h>

//UVa 815 Flooding!（排序）
//https://blog.csdn.net/qq_27474589/article/details/75416171
using namespace std;

int a[1000];

int main() {
    int m, n, cubi, cnt = 0;
    while (~scanf("%d%d", &m, &n) && m && n) {
        for (int i = 0; i < m * n; i++) scanf("%d", &a[i]);
        scanf("%d", &cubi);
        double cub = cubi * 1.0 / 100;
        sort(a, a + m * n);

        int sum = 0, i = 0, last = 0;
        double high, percent;

        for (i = 1; i < m * n && (cub - sum) > 0; i++) {
            last = sum;
            sum += i * (a[i] - a[i - 1]);
        }
        //高度为零，还需要特判
        if (cub == 0) {
            high = a[0];
            percent = 0;
        } else if (i == m * n && (cub - sum) > 0) {//水填满了最高海拔的格子，还有多的水
            high = (cub - sum) * 1.0 / i + a[i - 1]; //平分这些水
            percent = 100; //100%覆盖
        } else {
            /*水没有填满最高海拔的格子，在中间时就不够用了。
            这里用到sum的上一次结果，所以上面for循环中用了last保存。*/
            high = (cub - last) * 1.0 / (i - 1) + a[i - 2];
            percent = (i - 1) * 1.0 / (m * n) * 100;
        }
        printf("Region %d\n", ++cnt);
        printf("Water level is %.2f meters.\n", high);
        printf("%.2f percent of the region is under water.\n\n", percent);//注意空行在最后面
    }
    return 0;
}