CF 617E

#include<cstdio>
#include<algorithm>
#include<cmath>
#include<iostream>
#define FOR(i,s,t) for(register int i=s;i<=t;++i)
using std::sort;
using std::cout;
typedef long long ll;
const int N=100011;
const int M=2000011;
int blo;
struct question{
	int l,r,id;
	inline bool operator<(question A)const{
		return l/blo<A.l/blo||(l/blo==A.l/blo&&r/blo<A.r/blo);
	}
}q[N];
int n,m,k,l,r;
ll tot;
int hv[M],a[N];
ll ans[N];
inline void add(int x){tot+=1ll*hv[x^k];++hv[x];}
inline void del(int x){--hv[x];tot-=1ll*hv[x^k];}
int main(){
	scanf("%d%d%d",&n,&m,&k);
	blo=sqrt(n);
	FOR(i,1,n){
		scanf("%d",a+i);
		a[i]^=a[i-1];
	}
	FOR(i,1,m){
		scanf("%d%d",&q[i].l,&q[i].r);
		--q[i].l;
		q[i].id=i;
	}
	sort(q+1,q+m+1);
	l=1,r=0;
	FOR(i,1,m){
		while(l<q[i].l)del(a[l++]);
		while(q[i].l<l)add(a[--l]);
		while(r<q[i].r)add(a[++r]);
		while(q[i].r<r)del(a[r--]);
		ans[q[i].id]=tot;
	}
	FOR(i,1,m)cout<<ans[i]<<‘\n‘;
	return 0;
}