function Main(input) {
    n = parseInt(input);
    ans = a(n);
    console.log('%f', ans);
}
function a(n) {
    if(false) {
    } else if(n === 0) {
        return 4;
    } else if(n === 1) {
        return 3;
    } else {
        return a(n-1) * 3 / 4;
    }
}
// Don't edit this line!
Main(require("fs").readFileSync("/dev/stdin", "utf8"));