2003A

process.stdin.resume();
process.stdin.setEncoding("utf-8");

let inputString = "";
let currentLine = 0;

process.stdin.on("data", (inputStdin) => {
    inputString += inputStdin;
});

process.stdin.on("end", (_) => {
    inputString = inputString
        .trim()
        .split("\n")
        .map((string) => {
            return string.trim();
        });

    main();
});

function readline() {
    return inputString[currentLine++];
}

function main(){
    let testCases = parseInt(readline());
    for(let T = 1; T<=testCases; T++){
        let size = parseInt(readline());
        let myStr = readline();
        if(myStr[0] !== myStr[size-1]){
            console.log("yes");
        }else{
            console.log("no");
        }
    }
}