#include<bits/stdc++.h>
using namespace std;
const int N=2e5+10;
int a[N];
int n,x;
char c;
int main()
{
cin>>n;
int l=0,r=-1;
while(n--)
{
cin>>c>>x;
if(c=='L')
a[x]=--l;
else if(c=='R')
a[x]=++r;
else
cout<<min(r-a[x],a[x]-l)<<endl;
}
}