#include<bits/stdc++.h>
[[maybe_unused]] typedef long long ll;
[[maybe_unused]] const int N = (int) 1e6 + 20;
[[maybe_unused]] const int mod = (int) 1e9 + 7;
[[maybe_unused]] char endl = '\n';
[[maybe_unused]] char space = ' ';
[[maybe_unused]] const int off = 1 << 18;
void Run();
int main()
{
Run();
//in
int t = 1;
// std::cin >> t;
while (t--) {
int n,d,m;
std::cin >> n >> d >> m;
std::vector<int> v(m);
for (auto &item: v) {
std::cin >> item;
}
//ops
//out
std::cout << *std::max_element(v.begin(), v.end());
}
return 0;
}
void Run(){
std::ios_base::sync_with_stdio(false);std::cin.tie(nullptr);std::cout.tie(nullptr);
#ifndef ONLINE_JUDGE
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
#endif
}
