#include <stdio.h>
int p2()
{
    int a = 0, b = 1, sum = 0;
    while (b <= 4000000) {
        int next = a + b;
        if (next % 2 == 0)
            sum += next;
        a = b;
        b = next;
    }
    printf("%d\n", sum);
    return 0;
}