#include <bits/stdc++.h>
using namespace std;
 
#define fastIO() ios::sync_with_stdio(false); cin.tie(nullptr);
 
void solve() {
    int n;
    cin >> n;
 
    string a, b;
    cin >> a >> b;
 
    int pos = 0;
 
    // Find best switching position
    while (pos + 1 < n && a[pos + 1] <= b[pos]) {
        pos++;
    }
 
    // Build smallest string
    string result = a.substr(0, pos + 1) + b.substr(pos);
 
    cout << result << "\n";
    cout << pos << "\n";
}
 
int main() {
    fastIO();
    int t;
    cin >> t;
    while (t--) solve();
    return 0;
}

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