int buildSegmentTree(int begin,int end,int rootIndex){
segmentTree[rootIndex].begin=begin;
segmentTree[rootIndex].end=end;
if(end-begin==1)
segmentTree[rootIndex].max=sections[begin].end-sections[begin].begin;
else{
int mid=(begin+end)/2;
segmentTree[rootIndex].max=std::max(buildSegmentTree(begin,mid,leftChild(rootIndex)),
buildSegmentTree(mid,end,rightChild(rootIndex)));
}
return segmentTree[rootIndex].max;
}
int main(){
while(true){
scanf("%d",&sequenceNum);
if(sequenceNum==0)
return 0;
int queryNum;
scanf("%d",&queryNum);
for(int sequenceIndex=0;sequenceIndex<sequenceNum;sequenceIndex++)
scanf("%d",sequence+sequenceIndex);
splitIntoSections();
buildSegmentTree(0,sectionNum,0);
while(queryNum--){
int begin,end;
scanf("%d%d",&begin,&end);
begin--;
if(sequence[begin]==sequence[end-1]){
printf("%d\n",end-begin);
continue;
}
int firstSectionIndex=findSectionIndex(sequence[begin]);
int firstSectionLen=sections[firstSectionIndex].end-begin;
int lastSectionIndex=findSectionIndex(sequence[end-1]);
int lastSectionLen=end-sections[lastSectionIndex].begin;
int midSectionLenMax=querySegmentTree(firstSectionIndex+1,lastSectionIndex,0);
printf("%d\n",std::max(midSectionLenMax,std::max(firstSectionLen,lastSectionLen)));
}
}
}
NumArray(vector<int> &nums) {
numbers = nums;
if(nums.size() >= 1){
rootNode = buildSegmentTree(0, 0, nums.size()-1, nums);
}
}
