import java.util.Scanner; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); // 注意 hasNext 和 hasNextLine 的区别 while (in.hasNextLine()) { // 注意 while 处理多个 case int length = in.nextInt(); String a = in.next(); String b = in.next(); String[] strings = new String[length]; int j = 0; while(in.hasNext()){ strings[j] = in.next(); j++; } in.nextLine(); // 消耗掉 nextInt() 后的换行符 int prev1 = -1; int prev2 = -1; int ret = Integer.MAX_VALUE; for (int i = 0; i < length; i++) { if (strings[i].equals(a)) { prev1 = i; if (prev2 != -1) { ret = Math.min(ret,i-prev2); } } if (strings[i].equals(b)) { prev2 = i; if (prev1 != -1) { ret = Math.min(ret,i-prev1); } } } System.out.println(ret == Integer.MAX_VALUE?-1:ret); } } }