const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void async function () {
// Write your code here
let arr = [];
for(let i = 0 ; i < 10 ; i++){
const total = parseInt(await readline());
if(total) {
let sum = total;
let res = 0;
while(sum >=3) {
const rest = sum % 3;
res += Math.floor(sum / 3);
sum = Math.floor( sum / 3) + rest;
}
if(sum >= 2) res++;
console.log(res)
}else {
break;
}
}
}()