#include <iostream>
using namespace std;
int fibonacci(int k)
{
if (k == 1 || k == 2)
return k;
return (fibonacci(k-1) + fibonacci(k-2));
}
int evenfibonacci()
{
int result = 0;
for (int k = 1; fibonacci(k) <= 4e6; ++k) {
if (fibonacci(k) % 2 == 0) {
result += fibonacci(k);
}
}
return result;
}
int main()
{
cout << evenfibonacci();
}
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