Let's introduce some definitions that will be needed later.
Let prime(x)prime(x) be the set of prime divisors of xx. For example, prime(140)={2,5,7}prime(140)={2,5,7}, prime(169)={13}prime(169)={13}.
Let g(x,p)g(x,p) be the maximum possible integer pkpk where kk is an integer such that xx is divisible by pkpk. For example:
- g(45,3)=9g(45,3)=9 (4545 is divisible by 32=932=9 but not divisible by 33=2733=27),
- g(63,7)=7g(63,7)=7 (6363 is divisible by 71=771=7 but not divisible by 72=4972=49).
Let f(x,y)f(x,y) be the product of g(y,p)g(y,p) for all pp in prime(x)prime(x). For example:
- f(30,70)=g(70,2)⋅g(70,3)⋅g(70,5)=21⋅30⋅51=10f(30,70)=g(70,2)⋅g(70,3)⋅g(70,5)=21⋅30⋅51=10,
- f(525,63)=g(63,3)⋅g(63,5)⋅g(63,7)=32⋅50⋅71=63f(525,63)=g(63,3)⋅g(63,5)⋅g(63,7)=32⋅50⋅71=63.
You have integers xx and nn. Calculate f(x,1)⋅f(x,2)⋅…⋅f(x,n)mod(109+7)f(x,1)⋅f(x,2)⋅…⋅f(x,n)mod(109+7).
Input
The only line contains integers xx and nn (2≤x≤1092≤x≤109, 1≤n≤10181≤n≤1018) — the numbers used in formula.
Output
Print the answer.
Examples
input
Copy
10 2
output
Copy
2
input
Copy
20190929 1605
output
Copy
363165664
input
Copy
947 987654321987654321
output
Copy
593574252
Note
In the first example, f(10,1)=g(1,2)⋅g(1,5)=1f(10,1)=g(1,2)⋅g(1,5)=1, f(10,2)=g(2,2)⋅g(2,5)=2f(10,2)=g(2,2)⋅g(2,5)=2.
In the second example, actual value of formula is approximately 1.597⋅101711.597⋅10171. Make sure you print the answer modulo (109+7)(109+7).
In the third example, be careful about overflow issue.
题解:这是到算贡献的题,不难发现,有一种暴力解法就是对于n遍历求出贡献,但显然对于1e18的数据,会tle,因此我们可以换一种思路,对于素因子来说,他的贡献显然是指他的倍数
代码:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
const int MOD = 1000000007;
int x;
long long n;
int p[100], pn = 0;
long long quickmul(int a, int b)
{
long long ret = 1;
for(; b; b >>= 1, a = (long long)a * a % MOD)
if(b & 1)
ret = ret * a % MOD;
return ret;
}
int main()
{
cin >> x >> n;
for(int i = 2; i * i <= x; i++)
if(x % i == 0)
{
p[++pn] = i;
while(x % i == 0)
x /= i;
}
if(x > 1)
p[++pn] = x;
int ans = 1;
for(int i = 1; i <= pn; i++)
{
long long now = n;
long long cnt = 0;
while(now > 0)
{
now /= p[i];
cnt += now;
}
cnt %= MOD - 1;
ans = ans * quickmul(p[i], cnt) % MOD;
}
cout << ans << endl;
return 0;
}