SQL connection and store procedure invocation

//CREATE PROC uspGetCity (@id nvarchar(5))
//AS
//SELECT City from Customers WHERE CustomerID = @id
//GO

using System;
using System.Data.SqlClient;

namespace DBTest
{
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection cnn;
            string connectionString = "Server=.;Database=Northwind;Integrated Security=true";
            cnn = new SqlConnection(connectionString);
            try
            {
                cnn.Open();
                Console.WriteLine("Connection Open ! ");
                //string sql = "Select * from customers";
                //string inputVal = Console.ReadLine();
                //string sql = "SELECT City from Customers WHERE CustomerID="+"'"+ Console.ReadLine()+ "'";
                string sql = "EXEC uspGetCity" + "'" + Console.ReadLine() + "'";
                var command = new SqlCommand(sql, cnn);
                var dataReader = command.ExecuteReader();
                while (dataReader.Read())
                {
                    Console.WriteLine(dataReader.GetValue(0));
                }
                dataReader.Close();
                command.Dispose();
                cnn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine("Can not open connection ! "+ex.Message);
            }
        }
    }
}