# B - How many integers can you find

Now you get a number N, and a M-integers set, you should find out how many integers which are small than N, that they can divided exactly by any integers in the set. For example, N=12, and M-integer set is {2,3}, so there is another set {2,3,4,6,8,9,10}, all the integers of the set can be divided exactly by 2 or 3. As a result, you just output the number 7.

```#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long ll;
ll a[500];
int main()
{
ll n, m;
while(~scanf("%lld%lld",&n,&m))
{

int top = 0;
for(int i = 0; i < m; ++ i)
{
ll x;
cin >> x;
if(x != 0)
a[top++] = x;
}
ll ans = 0,sum,num;
for(int i = 1; i < (1 << top); ++ i)
{
num=0,sum=1;
for(int j = 0; j < top; ++ j)
{
if((i >> j) & 1)
{
num++;
sum = sum * a[j] /(__gcd(sum, a[j]));
}
}
if(num % 2)
{
ans += (n - 1) / sum;
}
else
{
ans -= (n - 1) / sum;
}
}
cout << ans << endl;
}
return 0;
}```

B - How many integers can you find

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