package chelper;

import io.InputReader;
import io.OutputWriter;
import misc.SimpleSavingChelperSolution;


public class TaskA extends SimpleSavingChelperSolution {

  public void solve(int testNumber, InputReader in, OutputWriter out) {
    wrapSolve(testNumber, in, out);
  }

  @Override
  public void solve(int testNumber) {
    int n = in.nextInt();
    char[] c = in.nextString().toCharArray();
    String s = in.nextString();
    boolean horizontal = false;
    if (s.contains("T")) {
      horizontal = true;
    }
    if (c[n - 1] == 'B' || c[n - 1] == 'T') {
      if (horizontal) {
        out.println(3);
      } else {
        out.println(2);
      }
    } else {
      if (horizontal) {
        out.println(2);
      } else {
        out.println(3);
      }
    }
  }
}