#include<bits/stdc++.h>
#define ll long long
#define N 100001
using namespace std;
ll n,q,l,r,ans,a[26][N],cnt[26],L,R,mid,id1,id2;
string s;
char id;
ll in(){
    ll k=0,f=1;
    char c=getchar();
    while(c<'0'||c>'9'){
        if(c=='-')f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9')k=k*10+c-'0',c=getchar();
    return k*f;
}
void out(ll x){
    if(x<0)putchar('-'),x=-x;
    if(x<10)putchar(x+'0');
    else out(x/10),putchar(x%10+'0');
}
int main(){
    freopen("Time.in","r",stdin);
    freopen("Time.out","w",stdout);
    n=in();
    q=in();
    getline(cin,s);
    s=' '+s;
    for(int i=1;i<=n;i++) a[s[i]-'a'][++cnt[s[i]-'a']]=i;
    while(q--){
        l=in();
        r=in();
        ans=-1;
        for(int i=0;i<26;i++){
            if(cnt[i]==0) continue;
            if(s[l]-'a'==i){
                id=i;
                continue;
            }
            L=1;
            R=cnt[i];
            while(L<R){
                mid=(L+R)/2;
                if(a[i][mid]>l) R=mid;
                else L=mid+1;
            }
            id1=L;
            L=1;
            R=cnt[i];
            while(L<R){
                mid=(L+R+1)/2;
                if(a[i][mid]<=r) L=mid;
                else R=mid-1;
            }
            id2=L;
            for(int j=id1;j<id2;j++) ans=max(ans,(a[i][j]-l)*(a[i][id2]-a[i][j]));
        }
        while(s[l+1]==s[l]) l++;
        l++;
        if(cnt[id]!=0){
            L=1;
            R=cnt[id];
            while(L<R){
                mid=(L+R)/2;
                if(a[id][mid]>l) R=mid;
                else L=mid+1;
            }
            id1=L;
            L=1;
            R=cnt[id];
            while(L<R){
                mid=(L+R+1)/2;
                if(a[id][mid]<=r) L=mid;
                else R=mid-1;
            }
            id2=L;
            for(int j=id1;j<id2;j++) ans=max(ans,(a[id][j]-l)*(a[id][id2]-a[id][j]));
        }
        out(ans);
        putchar('\n');
    }
    return 0;
}