using System;
using System.Collections.Generic;

namespace BasicFormatting
{
	public enum State {If, For};

	static class Data{
		public static string[] Input = { 
			"12",
			"····",
			"VAR I",
			"·FOR I=1 TO 31",
			"»»»»IF !(I MOD 3) THEN",
			"··PRINT \"FIZZ\"",
			"··»»ENDIF",
			"»»»»····IF !(I MOD 5) THEN",
			"»»»»··PRINT \"BUZZ\"",
			"··»»»»»»ENDIF",
			"»»»»IF (I MOD 3) && (I MOD 5) THEN",
			"······PRINT \"FIZZBUZZ\"",
			"··»»ENDIF",
			"»»»»·NEXT"
		}; 
	}

	class MainClass
	{
		public static void Main ()
		{
			var state = new List<State>() ;
			char[] spaceChars = { '»', '·' };
			var lines = Int32.Parse (Data.Input[0]);
			var indent = Data.Input[1];

			for (int line = 1; line < lines+1; line++) {
				var thisLine = Data.Input[line+1].TrimStart(spaceChars);

				if (thisLine.ToUpper ().StartsWith ("NEXT")) {
					if (state.Count>0 && state[state.Count - 1] == State.For) 
						state.RemoveAt (state.Count - 1);  
					else{
						throw new FormatException (String.Format ("NEXT without FOR (line: {0})", line));
					}
				}


				if (thisLine.ToUpper ().StartsWith ("ENDIF")) {
					if (state.Count>0 && state [state.Count - 1] == State.If)
						state.RemoveAt (state.Count - 1);
					else {
						throw new FormatException (String.Format ("ENDIF without IF (line: {0})", line));
					}
				}

				var indentChars = "";
				for (int ind = 0; ind < state.Count; ind++) {
					indentChars += indent;
				}
				thisLine = indentChars+thisLine;

				if(thisLine.ToUpper().TrimStart(spaceChars).StartsWith("IF ")) state.Add (State.If);
				if(thisLine.ToUpper().TrimStart(spaceChars).StartsWith("FOR ")) state.Add (State.For);
			
				Console.WriteLine(thisLine);
			}

			if(state.Count>0)
			{
				if(state.Contains (State.If)) Console.WriteLine ("ERROR: Not closed all IF Statements");
				if(state.Contains (State.For)) Console.WriteLine ("ERROR: Not closed all FOR Statements");
			}
		}
	}

	public class FormatException:Exception{
		public FormatException(string message):base(message)
		{
		}
	}

}