#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 2e5 + 10;
int l,r=-1;
int id[N];
int main()
{
int q;
scanf("%d",&q);
while(q -- ){
char c;
int x;
scanf(" %c %d",&c,&x);
if(c == 'L'){
id[x] = --l;
}
if(c == 'R'){
id[x] = ++r;
}
if(c == '?'){
printf("%d\n",min(id[x] - l,r - id[x]));
}
}
return 0;
}