#include<cstdio>
#include<queue>
using namespace std;
queue<int>q;
bool v[1005];
int findd(int x, queue<int>t)
{
    while(t.back()==x)
        t.pop();
    return t.size();
}
int main()
{
    freopen("coada1.in","r",stdin);
    freopen("coada1.out","w",stdout);
    int n,x;
    char ch,ch2,ch3,ch4,ch1;
    scanf("%d\n",&n);
    for(register int i=1;i<=n;i++)
    {
        scanf("%c",&ch);
        if(ch=='p')
        {
            scanf("%c%c%c ",&ch1,&ch2,&ch3);
            scanf("%d\n",&x);
            if(v[x]==0)
            {
                q.push(x);
                v[x]=1;
            }
                else
                {
                    while(q.back()!=x)
                    {
                        v[q.back()]=0;
                        q.pop();
                    }
                    v[x]=1;
                }
        }
            else
            {
                scanf("%c%c%c%c ",&ch1,&ch2,&ch3,&ch4);
                scanf("%d\n",&x);
                if(v[x]==0) printf("-1\n");
                    else printf("%d\n",findd(x,q));
            }
    }
    return 0;
}