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Time Limit: 1 s Memory Limit: 512 MB Total points: 100

#3472. 奇偶

Statistics

考虑如下函数 $f(X)$,它接受一个正整数作为参数,并返回一个整数。

function f(X):
    iterations := 0
    while X is not 1:
        if X is even:
            divide X by 2
        else:
            add 1 to X
        add 1 to iterations
    return iterations

可以证明,对于任何正整数 $X$,该函数都会终止。给定一个区间 $[L, R]$,计算总和 $$S = f(L) + f(L + 1) + \dots + f(R - 1) + f(R)$$

输入格式

输入的第一行包含两个整数 $L$ 和 $R$ ($1 \le L \le R \le 10^{18}$)。

输出格式

输出结果 $S$ 对质数 $10^9 + 7$ 取模后的值。

样例

样例输入 1

1 127

样例输出 1

1083

样例输入 2

74 74

样例输出 2

11

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