容斥原理练习题，忘记处理gcd 和 lcm，wa了几发0.0.

#include
     
      #include
      
       #include
       
        using namespace std;typedef long long ll;ll Num[30];ll gcd(ll a,ll b){    return b == 0 ? a : gcd(b,a%b);}int main(){    ll N, M;    while(scanf("%lld%lld",&N,&M)!=EOF)    {        N--;        ll num = 0;        ll tmp,Cnt = 0;        for(int i = 0; i < M; ++i)        {            scanf("%lld",&tmp);            if(tmp == 0) continue;            else {                Num[Cnt++] = tmp;            }        }        for(int i = 1; i < (1 << Cnt) ; ++i)        {            ll cnt = 0, tmp = 1;            for(int j = 0; j < Cnt; ++j)            {                if(i & (1 << j))                {                    cnt++;                    tmp =tmp /gcd(tmp,Num[j]) * Num[j];                }                //printf("%lld\n",tmp);            }            if(cnt & 1) num += (N/tmp);            else num -= (N/tmp);        }        printf("%lld\n",num);    }    return 0;}