C++ :

/* 最长好数组：A1 | A2 | ... 且严格递增 → 每个至少翻倍，故答案 = floor(log2(Y/X)) + 1 */
#include <cstdio>
int main(){
    long long X, Y;
    if(scanf("%lld %lld", &X, &Y) != 2) return 0;
    long long cur = X;
    int L = 1;
    while(cur <= Y / 2){ cur *= 2; L++; }
    printf("%d\n", L);
    return 0;
}