#include <iostream>
#include <cassert>
using namespace std;
using ll=long long;
const int MN=5e5+13, ML=22;
const int inf32=1e9;
int N, Q; ll K;
ll A[MN], pre[MN];
int nxt[MN][ML]; ll wgt[MN][ML];
int main()
{
cin>>N>>Q>>K;
for (int i=1; i<=N; i++)
{
cin>>A[i];
if (i&1) pre[i]=pre[i-1]+A[i];
else pre[i]=pre[i-1]-A[i];
}
//pre[N+2]=pre[N+1]=pre[N];
for (int x=1; x<=N; x+=2)
{
int y=x;
while (y+2<=N && (pre[y]-pre[x-1])%K>=A[y+1])
{
y+=2;
assert(pre[y]>=pre[x-1]);
}
wgt[x][0]=(pre[y]-pre[x-1])/K;
nxt[x][0]=y;
//cerr<<x<<" TO "<<y<<": "<<wgt[x][0]<<endl;
}
for (int j=1; j<ML; j++)
{
for (int i=1; i<=N; i++)
{
if (nxt[i][j-1]+2>N) nxt[i][j]=inf32;
else
{
nxt[i][j]=nxt[nxt[i][j-1]+2][j-1];
wgt[i][j]=wgt[i][j-1]+wgt[nxt[i][j-1]+2][j-1];
}
}
}
while (Q--)
{
int L, R; cin>>L>>R;
if (!(L&1)) L++;
if (!(R&1)) R--;
if (L>R)
{
cout<<0<<endl;
continue;
}
ll ans=0;
for (int i=ML-1; i>=0; i--)
{
//cerr<<L<<' '<<i<<": "<<nxt[L][i]<<' '<<wgt[L][i]<<endl;
assert(L&1);
if (L<=N && nxt[L][i]<=R)
{
ans+=wgt[L][i];
L=nxt[L][i]+2;
}
}
cout<<ans<<endl;
}
return 0;
}
