# include <algorithm> # include <iostream> # include <cstring> # include <cmath> using namespace std; long long L,N,M,D[100005]; bool check(long long x){ long long sum = 0; long long s = 0; for (long long i = 1;i <= N + 1;i++){ if (D[i] - s < x) sum++; else s = D[i]; }return sum <= M; }long long BinarySearch(){ long long left = 1,right = L; D[N + 1] = L; while (left + 1 < right){ long long mid = (left + 1 + right) >> 1; if (check(mid)) left = mid; else right = mid; }if (check(right)){ left = right; }return left; }int main(){ cin >> L >> N >> M; for(int i = 1;i <= N;i++) cin>>D[i]; cout << BinarySearch(); return 0; }