using System; using System.Linq; using System.Collections.Generic; class Program { static void Main() { int d = ri(); var c = new char[14]; for(int i = 0; i < 2; i++) { var t = rs(); for(int j = 0; j < 7; j++) c[i * 7 + j] = t[j]; } int ans = 0; for(int i = 0; i < 14 - d + 1; i++) { int cnt = 0; int cnt2 = 0; var a = new bool[14]; for(int j = 0; j < 14; j++) if (c[j] == 'o') a[j] = true; for (int j = i; j < i + d; j++) a[j] = true; for(int j = 0; j < 14; j++) { if (a[j]) cnt2++; else cnt2 = 0; cnt = Math.Max(cnt, cnt2); } ans = Math.Max(ans, cnt); } Console.WriteLine(ans); } #region Scan static int ri() { return int.Parse(Console.ReadLine()); } static long rl() { return long.Parse(Console.ReadLine()); } static double rd() { return double.Parse(Console.ReadLine()); } static string rs() { return Console.ReadLine(); } static int[] ria() { return Console.ReadLine().Trim().Split().Select(int.Parse).ToArray(); } static long[] rla() { return Console.ReadLine().Trim().Split().Select(long.Parse).ToArray(); } static double[] rda() { return Console.ReadLine().Trim().Split().Select(double.Parse).ToArray(); } static string[] rsa() { return Console.ReadLine().Trim().Split(); } static void mul(out int a, out int b) { var arr = ria(); a = arr[0]; b = arr[1]; } static void mul(out int a, out int b, out int c) { var arr = ria(); a = arr[0]; b = arr[1]; c = arr[2]; } static void mul(out int a, out int b, out int c, out int d) { var arr = ria(); a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; } static void mul(out long a, out long b) { var arr = rla(); a = arr[0]; b = arr[1]; } static void mul(out long a, out long b, out long c) { var arr = rla(); a = arr[0]; b = arr[1]; c = arr[2]; } static void mul(out long a, out long b, out long c, out long d) { var arr = rla(); a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; } #endregion #region Math const int mod = 1000000007; static bool isprime(long n) { if (n < 2) return false; for (long i = 2; i * i <= n; i++) if (n % i == 0) return false; return true; } static long gcd(long a, long b) { return a == 0 ? b : gcd(b % a, a); } static long lcm(long a, long b) { return a * b / gcd(a, b); } #endregion }