codeforces1335B

#include<bits/stdc++.h>
using namespace std;
const int N = 30;
char arr[N];
int main(){
    int t;
    cin>>t;
    while(t--){
    	int n,a,b;
    	cin>>n>>a>>b;
    	int x=0;
    	for(char i = 'a';i<='z';i++)
    		arr[x++]=i;
    	for(int i=0,j=0,cnt=0;i<n;j++){
    		if(j==n)
    			break;
    		cout<<arr[i];
    		if(i<b-1)
    			i++;
    		if(cnt==a-1){
    			i=0;
    			cnt=0;	
    		}
    		else
    			cnt++;
	}
		cout<<endl;
    }
    return 0;
}