华为机试 计算字符个数

sing System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace test
{
    class Program
    {
        static void Main(string[] args)
        {
            
                  string str = Console.ReadLine().ToLower();
            //string str="""";
            string str2 = Console.ReadLine().ToLower();
            char[] c = str.ToCharArray();
            int num = 0;
            for (int i = 0; i < c.Length; i++)
            {
                if (str2 == c[i].ToString())
                {
                    num++;
                }
            }
            //string[] a = str.Split(‘ ‘);
            //int b = a[a.Length - 1].Length;
            Console.WriteLine(num);
            Console.ReadKey();
        }
    }
}