///coada alocata static
#include <bits/stdc++.h>
#define N 50001
using namespace std;
ifstream fin("coada1.in");
ofstream fout("coada1.out");

int q[N], v[1001],n,x, indx,dim;
char s[10];
int main()
{
    fin>>n;
    indx=0,dim=0;
    for(int i=1; i<=n; i++)
    {
        fin>>s>>x;
        if(s[0]=='p')
        {
            if(v[x]>indx)
            {
                indx=v[x],q[++dim]=x, v[x]=dim;
            }
            else if(v[x]<=indx)q[++dim]=x, v[x]=dim;
        }
        else
        {
            if(v[x]>indx)fout<<v[x]-indx<<"\n";
            else fout<<-1<<'\n';
        }
    }
    return 0;
}