#include<bits/stdc++.h> using namespace std; using namespace std; const int MAXX=100010; bool isvi[MAXX]; void count(){ isvi[1]=1; for(int i=2;i<MAXX;i++){ isvi[i]=0; } for(int i=2;i*i<MAXX;i++){ if(!isvi[i]){ for(int j=i*i;j<=MAXX;j+=i){ isvi[j]=1; } } } } int main(){ int a,b; count(); while(scanf("%d%d",&a,&b)!=EOF){ long long sum=0; if(a>b){ swap(a,b); } if(a==b){ cout<<0<<endl; continue; } for(int i=a+1;i<b;i++){ if(!isvi[i]){ sum+=i; } } printf("%lld\n",sum); } } |
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