I tried to solve the task but it says there is an error that the program did not accept

using System;

class City
{
private string namn;
private int temp;

public City(string namn, int temp)
{
this.namn = namn;
this.temp = temp;
}

public override string ToString()
{
return $"City: {namn}, Temperatur: {temp} grader Celsius";
}
}

class Program
{
static int LinearSearch(City[]cities, int n, int söktemp)
{
for (int i = 0; i < n; i++)
{
if (cities[i].ToString().Contains($"Temperatur: {söktemp}"))
{
return i; // Returnera indexet om temperaturen hittas
}
}

return -1; // Returnera -1 om temperaturen inte hittas
}

static void BubbleSort(City[] cities, int n)
{
for (int i = 0; i < n - 1; i++)
{
for (int j = 0; j < n - i - 1; j++)
{
// compare the temperatures and switch places if the first is higher and the second
if (cities[j].ToString().Contains("Temperatur") && cities[j + 1].ToString().Contains("Temperatur"))
{
int temp1 = int.Parse(cities[j].ToString().Split(':')[1].Trim().Split(' ')[0]);
int temp2 = int.Parse(cities[j + 1].ToString().Split(':')[1].Trim().Split(' ')[0]);

if (temp1 < temp2)
{
// switch place
City tempCity = cities[j];
cities[j] = cities[j + 1];
cities[j + 1] = tempCity;
}
}
}
}
}

static void Main()
{
// Declare a field Cities with four cities
City[] cities = new City[4];

// Let the user feed in cities och temperaturer
for (int i = 0; i < 4; i++)
{
Console.Write($"Enter namn för city {i + 1}: ");
string namn = Console.ReadLine();

Console.Write($"Enter temperatures for city {i + 1}: ");
int temp = int.Parse(Console.ReadLine());

cities[i] = new City(namn, temp);
}

// Sort the field cities
BubbleSort(cities, 4);

// Prent the cities in order of temperature
Console.WriteLine("\nCities efter temperatursortering:");
foreach (var city in cities)
{
Console.WriteLine(city.ToString());
}

// the user enters the temperature to search for
Console.Write("\nEnter temperatur to search after: ");
int searchtemp = int.Parse(Console.ReadLine());

// Call LinearSearch and print the result
int result = LinearSearch(cities, 4, searchtemp);
if (result != -1)
{
Console.WriteLine($"\nCity with temperatur {searchtemp}was found on index {result}.");
}
else
{
Console.WriteLine($"\nno with temperatur {searchtemp} found on.");
}
}
}