#include <bits/stdc++.h>


using namespace std;

const int N = 100100;

bool a[2][N];


int main() {

    int T;
    scanf("%d",&T);
    while(T--) {
        memset(a,false,sizeof(a));
        int n;
        int ix,pos,mpos = 0;
        scanf("%d",&n);
        for(int i = 0;i<n;i++) {
            scanf("%d %d",&ix,&pos);
            a[ix-1][pos] = true;
            mpos = max(mpos,pos);
        }
        int ans = 0 ;
        for(int i = 1;i<=mpos;i++) {
            if(a[0][i] ==false && a[1][i]==false) {
                continue ;
            }
            if(a[1][i]) {
                if(a[0][i+1] == false) {
                    ans = max(ans,i+2);
                } else {
                    ans = max(ans,i+3);
                }
            } else {
                ans = max(ans,i+1);
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}

/*
int check(int x, int y,int  z) {
    int numx = 1000;
    int numy = 1000;
    int numz = 1000;
    int ans = min((1000+x-1)/x,(1000+y-1)/y);
    numx -= ans * y;
    numy -= ans * x;
    if(numx<=0) {
        ans += min((1000+y-1)/y,(numy+z-1)/z);
    } else {
        ans += min((1000+x-1)/x,(numx+z-1)/z);
    }
    return ans;
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--) {
        int x,y,z;
        scanf("%d %d %d",&x,&y,&z);
        int ans = 1000;
        ans = min(ans,check(x,y,z));
        ans = min(ans,check(x,z,y));
        ans = min(ans,check(y,z,x));
        printf("%d\n",ans);

    }
    return 0;
}
*/