<?xml version="1.0" encoding="utf-8"?>
<response>116363111</response>

NSString *xmlString = @"<?xml version="1.0" encoding="utf-8"?>n<response>116363111</response>";

NSString *startTag = @"<response>";
NSString *endTag = @"</response>";
NSString *responseString;

NSScanner *scanner = [[NSScanner alloc] initWithString:xmlString];
[scanner scanUpToString:startTag intoString:nil];
scanner.scanLocation += [startTag length];
[scanner scanUpToString:endTag intoString:&responseString];
[scanner release];

NSLog(@"Response string is %@", responseString);