You are given sequence *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub> and *m* queries *l*<sub class="lower-index">*j*</sub>, *r*<sub class="lower-index">*j*</sub> (1 ≤ *l*<sub class="lower-index">*j*</sub> ≤ *r*<sub class="lower-index">*j*</sub> ≤ *n*). For each query you need to print the minimum distance between such pair of elements *a*<sub class="lower-index">*x*</sub> and *a*<sub class="lower-index">*y*</sub> (*x* ≠ *y*), that:
 -  both indexes of the elements lie within range [*l*<sub class="lower-index">*j*</sub>, *r*<sub class="lower-index">*j*</sub>], that is, *l*<sub class="lower-index">*j*</sub> ≤ *x*, *y* ≤ *r*<sub class="lower-index">*j*</sub>; -  the values of the elements are equal, that is *a*<sub class="lower-index">*x*</sub> = *a*<sub class="lower-index">*y*</sub>. 
The text above understands distance as |*x* - *y*|.
The first line of the input contains a pair of integers *n*, *m* (1 ≤ *n*, *m* ≤ 5·10<sup class="upper-index">5</sup>) — the length of the sequence and the number of queries, correspondingly. 

The second line contains the sequence of integers *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub> ( - 10<sup class="upper-index">9</sup> ≤ *a*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">9</sup>). 

Next *m* lines contain the queries, one per line. Each query is given by a pair of numbers *l*<sub class="lower-index">*j*</sub>, *r*<sub class="lower-index">*j*</sub> (1 ≤ *l*<sub class="lower-index">*j*</sub> ≤ *r*<sub class="lower-index">*j*</sub> ≤ *n*) — the indexes of the query range limits.
import sys
readline=sys.stdin.readline

class Dual_Segment_Tree:
    def __init__(self,N,f_act,e_act,operate,lst):
        self.N=N
        self.f_act=f_act
        self.e_act=e_act
        self.operate=operate
        self.lst=[None]*self.N
        for i,x in enumerate(lst):
            self.lst[i]=x
        self.segment_tree_act=[self.e_act]*(self.N+self.N)

    def __getitem__(self,i):
        if type(i) is int:
            if -self.N<=i<0:
                i+=self.N*2
            elif 0<=i<self.N:
                i+=self.N
            else:
                raise IndexError("list index out of range")
            self.Propagate_Above(i)
            return self.Operate_At(i)
        else:
            a,b,c=i.start,i.stop,i.step
            if a==None or a<-self.N:
                a=0
            elif self.N<=a:
                a=self.N
            elif a<0:
                a+=self.N
            if b==None or self.N<=b:
                b=self.N
            elif b<-self.N:
                b=0
            elif b<0:
                b+=self.N
            return self.lst[slice(a,b,c)]

    def Operate_At(self,i):
        return self.operate(self.lst[i-self.N],self.segment_tree_act[i])

    def Propagate_At(self,i):
        self.segment_tree_act[i<<1]=self.f_act(self.segment_tree_act[i<<1],self.segment_tree_act[i])
        self.segment_tree_act[i<<1|1]=self.f_act(self.segment_tree_act[i<<1|1],self.segment_tree_act[i])
        self.segment_tree_act[i]=self.e_act

    def Propagate_Above(self,i):
        H=i.bit_length()-1
        for h in range(H,0,-1):
            self.Propagate_At(i>>h)

    def Operate_Range(self,a,L=None,R=None):
        if L==None:
            L=self.N
        else:
            L+=self.N
        if R==None:
            R=self.N*2
        else:
            R+=self.N
        L0=L//(L&-L)
        R0=R//(R&-R)-1
        self.Propagate_Above(L0)
        self.Propagate_Above(R0)
        while L<R:
            if L&1:
                self.segment_tree_act[L]=self.f_act(self.segment_tree_act[L],a)
                L+=1
            if R&1:
                R-=1
                self.segment_tree_act[R]=self.f_act(self.segment_tree_act[R],a)
            L>>=1
            R>>=1

    def Update(self):
        for i in range(1,self.N):
            self.Propagate_At(i)
            self.segment_tree_act[i]=self.e_act

    def __str__(self):
        import copy
        segment_tree_act=copy.deepcopy(self.segment_tree_act)
        for i in range(1,self.N):
            segment_tree_act[i<<1]=self.f_act(segment_tree_act[i<<1],segment_tree_act[i])
            segment_tree_act[i<<1|1]=self.f_act(segment_tree_act[i<<1|1],segment_tree_act[i])
            segment_tree_act[i]=self.e_act
            segment_tree_act[i]=self.e_act
        return "["+", ".join(map(str,[self.operate(x,a) for x,a in zip(self.lst,segment_tree_act[self.N:])]))+"]"

N,M=map(int,readline().split())
A=list(map(int,readline().split()))
query=[[] for r in range(N+1)]
for m in range(M):
    l,r=map(int,readline().split())
    l-=1
    query[r].append((l,m))
ans_lst=[None]*M
prev={}
inf=1<<30
DST=Dual_Segment_Tree(N+1,min,inf,min,[inf]*(N+1))
for r in range(1,N+1):
    if A[r-1] in prev:
        i=prev[A[r-1]]
        DST.Operate_Range(r-1-i,0,i+1)
    prev[A[r-1]]=r-1
    for l,q in query[r]:
        ans=DST[l]
        if ans==inf:
            ans=-1
        ans_lst[q]=ans
print(*ans_lst,sep="\n")
