#include <iostream>
using namespace std;
const int N = 200010;
int a[N];
int main() {
int n;
cin >> n;
int l = 0;
int r = -1;
char c;
int d;
while (n--) {
cin >> c >> d;
if (c == 'L') {
a[d] = --l;
} else if (c == 'R') {
a[d] = ++r;
} else {
cout << min(a[d] - l, r - a[d]) << endl;
}
}
return 0;
}