#include <bits/stdc++.h>   using namespace std;   int n, m, k, i, dis = 10000000, temp, a[1000];   int main() {     cin >> n >> m >> k;     for (i = 0; i < n; ++i) cin >> a[i];     for (i = 0; i < n; ++i) {       if (a[i] != 0 && a[i] <= k) {         if (m <= i)           temp = (i - m + 1) * 10;         else           temp = (m - i - 1) * 10;         if (dis > temp) dis = temp;       }     }     cout << dis;     return 0;   }   