package chelper;

import io.InputReader;
import io.OutputWriter;
import solutions.ChelperSolution;


public class B extends ChelperSolution {

  @Override
  public void solve(int testNumber, InputReader in, OutputWriter out) {
    super.solve(testNumber, in, out);
  }

  @Override
  public void solve(int testNumber) {
    int n = in.nextInt();

    int maxLength = 0;
    int curLength = 0;

    for (int i = 0; i < n; i++) {
      int x = in.nextInt();

      if (x == 0) {
        curLength = 0;
      } else {
        curLength++;
        maxLength = Math.max(curLength, maxLength);
      }
    }

    out.println(maxLength);
  }
}