1 #include<cstdio> 2 #include<algorithm> 3 using namespace std; 4 bool vis[70000]; 5 int a,b; long long ans; 6 void Shai() 7 { 8     vis[1]=true; 9     for(long long i=2;i<=65536;i++)10       for(long long j=i*i;j<=65536;j+=i)11         vis[j]=true;12 }13 int main()14 {15     scanf("%d%d",&a,&b); Shai(); if(a>b) swap(a,b);16     for(int i=a+1;i<b;i++) if(!vis[i]) ans+=(long long)i;17     printf("%lld\n",ans);18     return 0;19 }