int i = 1;

while (i < 1000)
{
    NSString *num = [NSString stringWithFormat:@"%i", i];

    NSString *personURL = [@"https://api.themoviedb.org/3/person/" stringByAppendingString:num];

    personURL = [personURL stringByAppendingString:@"?api_key=XXXXXXXXXXXXXXXXXXXXX"];


    NSURLSession *session = [NSURLSession sharedSession];
    [[session dataTaskWithURL:[NSURL URLWithString:personURL]
            completionHandler:^(NSData *data,
                                NSURLResponse *response,
                                NSError *error) {


                NSString *strData = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

                NSError* errorJ;
                NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&errorJ];


                if(strData.length != 94 )// for an invalid ID
                {

                   [self.actors addObject:json];     //array in obj-c to hold all valid people
                }



            }]
     resume];
    i++;
}

That is all within one function receiving no parameters and only being called once. I feel like I am doing this wrong or forgetting something with the session since it takes a long time and is using a lot of memory. Please help me, Thank you in advance!