#include<bits/stdc++.h>
using namespace std;
void solve(){
int m,x,y;
cin>> m>> x>>y;
string s;
char val = 'a';
int j = 0;
for (int i = 0; i < m; i++)
{
s.push_back(val+j);
j++;
if(j>=y){
j = 0;
}
}
cout << s<<endl;
}
int main(){
int t;
cin>> t;
while (t--)
{
solve();
}
return 0;
}
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