Hacker Rank: Lonely Integer

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        
        NSCountedSet *numbers = [[NSCountedSet alloc]initWithCapacity:100];
        
        int count = 0;
        
        scanf("%d", &count);
        
        for (int i = 0; i< count; i++) {
            
            int num = 0;
            scanf("%d", &num);
            
            [numbers addObject:[NSNumber numberWithInt:num]];
        }
        
        [numbers enumerateObjectsUsingBlock:^(NSNumber *obj, BOOL * stop) {
            
            if ([numbers countForObject:obj] ==1){
                printf("%d",obj.intValue);
                *stop = YES;
            }
        }];
    }
    
    return 0;
}