#import <Foundation/Foundation.h>

int fib(int);

int main (int argc, const char * argv[])
{

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    int sum = 0, i = 0, x = fib(i++);
    while( x < 4000000 ) {
        if(x % 2 == 0)
            sum += x;
        x = fib(i++);

    }
    NSLog(@"answer: %d", sum);

    [pool drain];
    return 0;
}

int fib(int n) {
    if( n <= 1 )
        return n;

    return fib(n-1) + fib(n-2);
}