using System;
using System.Text.RegularExpressions;
public class StringContainsOnlyEnglish
{
public static bool IsOnlyEnglishLetters(string s)
{
string pattern = "^[a-zA-Z]+$";
return Regex.IsMatch(s, pattern);
}
public static void Main()
{
string s1 = "CSharp";
Console.WriteLine(IsOnlyEnglishLetters(s1));
string s2 = "CSharpCシャープ";
Console.WriteLine(IsOnlyEnglishLetters(s2));
}
}
/*
run:
True
False
*/