#include <stdio.h>

int main(void)
{
    int n = 0;
    int a = 3;

    while (a <= 10000)
    {
        a=2*a-1;
        n=n+1;
    }

    printf("初めて10000を超えるときのa%d = %d\n", n, a);

    return 0;
}