function Main(input) {
    const s = input.trim().split("\n");
    const n = parseInt(s.shift());
    let d = new Set([]);
    for (let i = 0; i < n; ++i) {
        for (let j = 0; j < n; ++j) {
            if (i == j) continue;
            d.add(s[i] + s[j]);
        }
    }
    console.log(d.size);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));