87分代码求助

#include<bits/stdc++.h>
using namespace std;
int n,m,a[1000005],p;
long long int l=1000000,r,c[1005],d[1005];
void pd(int x){
	if(x==1)return;
	if(x==2||x==3){p++;return;}
	if(x%6!=1&&x%6!=5)return;
	for(int z=5;z<=sqrt(x);z+=6){
		if(x%z==0||x%(z+2)==0)return;
	}
	p++;return;
}
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++){
		scanf("%lld%lld",&c[i],&d[i]);
		l=min(c[i],l);
		r=max(d[i],r);
	}
	for(int i=l;i<=r;i++){pd(i);a[i]=p;}
	for(int i=1;i<=n;i++){
	if(c[i]<1||d[i]>m)printf("Crossing the line\n");
	else {
	cout<<a[d[i]]-a[c[i]-1]<<endl;
		}}
	return 0;
}