(n,),a,(q,),*e=[[*map(int,s.split())]for s in open(0)]
uf=[*range(n)]
c=a[:]
def find(x):
 q=[]
 while uf[x]^x:q+=x,;x=uf[x]
 for p in q:uf[p]=x
 return x
def unite(x,y):
 x,y=find(x),find(y)
 if x^y:uf[x]=y;c[y]+=c[x];c[x]=0
for i in range(n-1):
  if a[i] and a[i+1]:
    unite(i,i+1)
for x,b in e:
  x-=1
  ans=c[find(x)]-a[x]+b
  if x and find(x-1)!=find(x):
    ans+=c[find(x-1)]
  if x+1<n and find(x)!=find(x+1):
    ans+=c[find(x+1)]
  print(ans)